Home / Articles / When Border Walls Work (and Don’t): An Open Memorandum to Mr. Trump
“A nation without borders is not a nation. There must be a wall across the southern border.” Statement on www.donaldjtrump.com
“These drug cartels are showing more and more indices of insurgencies.” Secretary Hillary R. Clinton (September 2010)
“In comparison to other global threats, the near collapse of societies in the hemisphere with the associated drug and [undocumented immigrant] flow are frequently viewed to be of low importance. Many argue these threats are not existential and do not challenge our national security. I disagree.” GEN John F. Kelly, USMC (July 2014), Commander, U.S. Southern Command
The presumptive Republican nominee, Donald J. Trump, has made the issue of controlling the southwestern border with Mexico a central tenet of his Presidential campaign. In his 2000 book, The America We Deserve, Mr. Trump summarized his position as “Immigration—Protecting Our Own.”
Mr. Trump often uses the tagline “America First,” one appropriated (intentionally or not) from the unilateralist political committee of the same name formed in the late 1930’s to oppose American intervention in Europe. While never explicitly adopting America First Committee planks, Mr. Trump’s musings on border security echo an AFC founding principle: “We must build a defense for our own shores so strong that no foreign power or combination of powers can invade out country.” Indeed, one of Mr. Trump’s former rivals, Senator Ted Cruz, went so far as to use that term—an invasion—to characterize unauthorized migration to the United States.
Perhaps if we are to look to the America First Committee for inspiration (or at least for trenchant lines) another of its four founding principles bears further reflection: “Humanitarian aid is the duty of a strong, free country…we should feed and clothe the suffering and needy people, and so keep alive their hope for the return of better days.”
It is a powerful statement of a unilateralist foreign policy, one under which the United States intervenes in defense of innocent peoples beyond its border.
The objective of this essay is to suggest that border walls, even when effective, address effects and not causes. What pushes unauthorized migrants toward the United States from our closest neighbors to the south—Mexico and the El Salvador-Guatemala-Honduras “Northern Triangle”—are powerful criminal insurgencies that have taken hold there and traffic in illegal narcotics. Endemic violence and lawlessness are pushing migrants to seek refuge in the United States. James Madison’s 1791 truism holds today: migration is always “from places where living is more difficult, to places where it is less difficult.” To lessen the impetus for unauthorized migration, life in those difficult places must be made less so. That starts with eradicating the criminal narco-insurgencies.
A border wall may indeed have a place in counterinsurgency—there are effective (if grim) examples of where walls have worked. But it would be immoral and un-American to construct a border wall without at the same time fulfilling our duty to protect refugees and vulnerable populations. Among the many unheeded lessons of the current Syria fiasco is that vulnerable populations must be protected in situ before they become refugees. At the same time the United States must vigorously attack the criminal narco-insurgencies with force proportionate to what they represent: an acute threat to American national and homeland security.
“We need strong borders. We need a wall.” So declared Donald J. Trump before the 2015 Conservative Political Action Conference. Mr. Trump has since reasserted and elaborated the point, including during the 10 November 2015 Republican debate:
“I will tell you, we are a country of laws. We need borders. We will have a wall. The wall will be built. The wall will be successful. And if you think walls don’t work, all you have to do is ask Israel. The wall works, believe me. Properly done. Believe me.”
Mr. Trump was referring to the so-called “West Bank barrier”—or “the wall,” as the International Court of Justice insisted—erected by the Israeli government in the West Bank, an area known formally as Occupied Palestinian Territory. A figurative wall, it is in reality “a multi layered composite obstacle comprised of several elements.”
Source: Israel Defense Ministry
Mr. Trump’s envisioned wall is intended to deter and frustrate illegal immigration across the United State-Mexico border.
“[Illegal immigration] was not a subject that was on anybody’s mind until I brought it up at my announcement. The fact is, since then, many killings, murders, crime, drugs are pouring across the border, our money going out and the drugs coming in. And I said we need to build a wall, and it has to be built quickly. And I don’t mind having a big beautiful door in that wall so that people can come into this country legally. But we need to build a wall, we need to keep illegals out.”
One question this statement begs is whether illegal immigration—or to use a more precise term, unauthorized migration—is cause or effect? Restated, does unauthorized migration produce the negative effects Mr. Trump elaborated, or instead, is unauthorized migration itself an effect of something larger? An impermeable, uncircumventable border wall (if such a thing can be said to exist) would no doubt stop all or substantially all unauthorized migrants from entering the United States (at least along its span). That being said, is unauthorized migration the source of the threat to American national and homeland security interests or is it another effect?
The author answers “causes”—civil violence, especially at high levels, unquestionably drives migration—and goes further: that the United States must discriminate “push” causal factors from chronic “pull” ones, and address the former forcefully. The author does not claim “pull” factors—economic migration and family unification are two examples—are unimportant. However, while unauthorized migration is the most visible manifestation of a porous border, it is substantially an effect of something far more serious, and not the cause of the criminal activity of which Mr. Trump is rightly concerned.
“We believe the United States must now concentrate all its energies on building a strong defense for this hemisphere.” -America First Committee (1939)
Western hemisphere defense was a founding principle of the unilateralist America First Committee, whose name has been appropriated by Mr. Trump’s campaign as a central theme. Today, the United States confronts a criminal insurgency to its south in the nearest neighboring states, one that seriously threatens to reduce the so-called “Northern Triangle” countries—El Salvador, Guatemala, and Honduras—from fragile states to a cluster of failed ones.
Source: Central Intelligence Agency World Factbook
That insurgency is a principal driver of unauthorized migration northward. Nearly one-tenth of the Northern Triangle’s 30 million residents have left so far, most for the United States, with about 100,000 migrating here yearly (of which 60 percent remain undocumented). The United States registered a sevenfold increase in asylum seekers at its southern border between 2009 and 2013, 70 percent of whom came from the Northern Triangle.
It is not the refugees fleeing violence in the Northern Triangle and Mexico who cause the conditions noted by Mr. Trump. Those conditions are spillover into the United States from the activities of criminal narco-insurgencies that operate throughout Mexico and the Northern Triangle, and increasingly, inside the United States itself.
What is a “criminal insurgency”? It is a criminal network comprised of multiple, often-transnational crime organizations that challenges the state’s monopoly on force. As an organized hierarchy with criminal, terrorist, and insurgent dimensions, a criminal insurgency differs from a “regular” one because its sole political motive is to gain autonomous economic control over territory. A criminal insurgency engages in what amounts to economic competition with the state. Most follow a “reverse ink-blot strategy. An inkblot (alternately, an “oil spot”) strategy is a variant of an enclave strategy. It involves a counterinsurgent pacifying a key node in which it establishes firm control and a secure base area. The counterinsurgent then methodically repeats the process to expand the secure area by pushing the inkblot’s perimeter outward. The reverse inkblot—one analyst team called it “a cruel parody” of its namesake—is a variant in which the insurgent’s objective is to generate as many sources of disorder within a state as possible. It hollows out a small piece of the state and establishes absolute dominion over it. If challenged, the insurgent responds violently, targeting government personnel and civilian populations.
The primary threat to American national and homeland security—and a main driver of unauthorized migration—is the cascade of sub-state criminal groups found throughout Mexico and the Northern Triangle. These include territorial criminal groups (especially borderland ones) many of which are associated with Mexican drug-trafficking organizations; transportistas, transnational trafficking networks; tumbadores, domestic organized crime groups; maras, transnational gangs; and pandillas, street gangs. Most unauthorized migration at some point involves human smuggling operations. Many of the same routes, networks, and organizations engaged in drug trafficking also traffic migrants along with weapons and other contraband. This is an important if often overlooked dimension: as the then-commander of the United States Southern Command, General John F. Kelly, USMC, testified before Congress in 2015, “terrorist organizations could seek to leverage those same smuggling routes to move operatives with intent to cause grave harm to our citizens or even bring weapons of mass destruction into the United States.”
Bedeviled by a long history of conflicts and corruption, the Northern Triangle is a strategically located transshipment point for Andean Ridge narcotics heading to the United States. While drug traffickers have operated in the Northern Triangle since the 1980s, increased interdiction efforts in the Caribbean starting in the 1990s led Columbian cartels to favor overland routes through Central America and Mexico. According to the United States State Department, 80 percent of documented drug flow from South America now transits the Northern Triangle.” Formal border crossings among Mexico, Guatemala, El Salvador, and Honduras appear as red dots in the map reproduced below:
Much of its terrain is remote, sparsely populated, and under-governed, making it ideal for traffickers. The region is wracked by endemic violence. A total of 17,422 murders were recorded there in 2015, up 11 percent from the prior year. The increase occurred mostly in El Salvador, which experienced a twofold increase in its murder rate between 2012 and 2015 as an earlier truce unraveled between the country’s two main maras or transnational gangs, Mara Salvatrucha (aka “MS-13”) and Barrio 18 (aka “Mara 18” or “M-18,” originally the 18th Street Gang).
“The illegal immigrant crime problem is far more serious and threatening than most people understand…MS-13 represents a lethal threat to both our citizens and illegal immigrants.” -Donald J. Trump (2015)
Though the exact number of street gang members or mareros in the Northern Triangle is unknown, informed estimates start at 50,000. The United States State Department speculated in 2012 there could be as many as 85,000 MS-13 and M-18 mareros in the Northern Triangle. The United Nations Office on Drugs and Crime put this number at 54,000, with roughly 20,000 mareros in El Salvador, 12,000 in Honduras, and 22,000 in Guatemala. The highest concentration is found in El Salvador where the rate of gang membership is double that of Guatemala and Honduras.
Many refugees of the civil conflict that raged in El Salvador and Guatemala in the 1980s and early 1990s settled in Los Angeles. MS-13 and M-18 started in these immigrant communities, eventually spreading south into Central America and Mexico. This happened largely as an unintended consequence of changes to United States immigration policy. The Illegal Immigrant Reform and Immigrant Responsibility Act of 1996 increased the number of criminal charges for which a foreign-born resident could be deported to their country of origin after serving a prison sentence here. The Federal government applied the new deportation policy aggressively to gang members in California, one result of which was a sudden influx of MS-13 and M-18 members into the Northern Triangle and parts of Mexico. Two decades hence, maras are active in even the smallest Northern Triangle villages and membership comprises a significant share of male youth. Interestingly, Nicaragua has a significant number of mareros but not MS-13 or M-18 members. Some speculate this is because Nicaragua experienced far fewer deportations from the United States than Mexico or the Northern Triangle countries.
A 2007 RAND study described the Northern Triangle’s northern border with Mexico’s Chiapas as “an ungoverned territory.” The six hundred-plus mile frontier “is plagued by poverty, violence, corruption, and an overall lack of state presence. It is an important transit zone for drugs, humans, and other contraband headed northward. The United States has a critical interest in the re-assertion of effective state control in this region. The Migration Policy Institute reports that partly due to pressure by the United States, the Mexican government’s Southern Border Plan (Programa Frontera Sur):
“significantly stepped up immigration enforcement along its border with Guatemala and along popular migrant routes in the interior. While apprehensions at the U.S. border fell, apprehensions in Mexico rose significantly, suggesting that outflows from Central America remained fairly stable throughout 2015; Mexican authorities apprehended many migrants before reaching the U.S. border. Indeed, though the combined apprehensions of Honduran, Salvadoran, and Guatemalan nationals by the United States and Mexico fell from 341,000 in FY 2014 to 301,000 in FY 2015, Mexico’s share of apprehensions increased from about 30 percent to 55 percent.”
These figures show it is possible to interdict unauthorized migrants at the Northern Triangle-Mexican border, though of course they say nothing about the conditions causing unauthorized migration in the first place. The current USSOCOM Commander stated in March that while Mexico’s apprehensions at its southern border have increased dramatically over the past three years:
“In El Salvador, Guatemala, and Honduras, many of the conditions that caused the 2014 migration crisis of unaccompanied children—high homicide rates, chronic poverty, and lack of economic opportunity—remain the same or are worsening, leading the UN High Commissioner for Refugees to call for action to respond to the ‘looming refugee crisis’ in the region.”
While the “U.S. Strategy for Engagement in Central America” is intended to address root economic causes of migration in parallel to the Central American Regional Security Initiative’s focus on transnational and national organized crime, these programs are substantially under-resourced relative to the threat.
“It is a scandal when America cannot control its own borders.” -Donald J. Trump (2000)
“The point is that properly built walls work.” -Donald J. Trump (2015)
A controlled border is a secure one. And the essence of border security is interdiction: as the United States Army counterinsurgency manual authored by General David H. Petreus observes, “insurgencies often rely heavily on freedom of movement across porous borders.”
Mr. Trump’s example of Israel’s West Bank barrier-cum-wall sits roughly in the middle of a continuum, one end of which is defined by Hungary’s border fence erected to exclude unauthorized migrants seeking to enter the European Union. At the other end lies the Morice Line, which France constructed in 1957 along a 200-mile stretch of the Algerian-Tunisian frontier.
Hungary’s border fence is just that—a fence—which features a 13-foot high chain link span fronted by razor wire and patrolled by armed troops to prevent unauthorized migrants from entering Hungary from the Balkan countries to its south. Hungary has effectively quarantined itself from Croatia and Serbia—while over 200,000 unauthorized migrants entered Hungary between September and October of 2015, fewer than 1,000 crossed into Hungary during January 2016—but the fence has proved something of a boon for human smugglers. Austria has threatened to do likewise and erect a border fence to halt the flow of unauthorized migrants entering the country from Italy through the Brenner Pass.
The United States has erected non-continuous vehicle barriers and pedestrian fencing along the border with Mexico (along with camera and sensor-based “virtual fence” pilot projects in Arizona, which the Department of Homeland Security discontinued). In 2007 the Customs and Border Patrol (CPB) funded a project called “Fence Lab” to test fence and barrier prototypes, which were evaluated based on performance criteria such as their ability to disable a vehicle traveling at 40 miles per hour. Through January 2010, CBP completed roughly 643 miles of fencing (344.8 miles of primary pedestrian fence and 298.5 miles of vehicle barriers). By February 2012, CPB had completed 651 miles of fencing (352 miles of pedestrian fence and 299 miles of vehicle barriers).
These barriers may frustrate the efforts of unauthorized migrants to enter the United States but are largely ineffective against criminal insurgents. The first step of a counterinsurgent border security initiative is to build and maintain defensive barriers, the purpose of which is to reduce border porousness and make infiltration difficult. In other words, “the best offense is a good fence.” Both India and Israel rely heavily on fences and border-defense systems enforced by barrier-and-pursuit strategies.
Perhaps the most striking example of an impermeable barrier dates to the French counterinsurgency in Algeria in the late 1950s. The Morice Line ran for some 200 miles along the Algerian-Tunisian border, from the Mediterranean coast south to the Sahara Desert. It was defended by a total force of 80,000 French personnel, 30,000 of which were directly deployed along the Line and a less elaborate one on the Algeria-Morocco border. The Morice Line presented a lethal barrier to insurgents: an eight-foot high 5000 volt electric fence buffered on both sides by a 45 meter deep minefield, and on the Algerian side by an additional barbed wire entanglement patrolled 24 hours a day. An automatic alarm activated in the event the electric fence was breached triggered an immediate response from 105mm howitzers and a mobile strike force comprised of helicopters, tanks, and airborne infantry. Algerian Front de Libération Nationale (FLN) insurgents based in Tunisia tried a variety of measures to defeat the Morice Line including tunneling under it and building ramps over it. French countermeasures decisively defeated all these efforts and within the first seven months of the Morice Line’s construction, the FLN lost over 6,000 personnel and 4,300 weapons during attempts to cross the Line. Perhaps as important, some 15,000 to 20,000 FLN insurgents (an estimated 20-50 percent of its total force) were stranded in Tunisia from 1958 through the war’s conclusion in 1962 because the FLN was unable to penetrate the Morice Line.
The United States-Mexico border runs 1,989 miles from Tijuana east to Brownsville, some ten times the length of the Morice Line. Even if unauthorized migrants could be kept away from such a lethal barrier, the time and resources to build and operate it are hard to fathom. Moreover, the suggestion of a lethal barrier to prevent unauthorized migration is morally repugnant. The toll of the World War I era Dodendraad or “Death Wire”—an electric fence erected by Imperial Germany along the Netherlands-Belgium border that killed an estimated 2,000-3,000 noncombatants—should disabuse anyone inclined to entertain such a proposal to control unauthorized migration.
“Insurgents succeed by sowing chaos and disorder anywhere; the government fails unless it maintains a degree of order everywhere.” -United States Army Field Manual 3-24 Counterinsurgency.
Mr. Trump wrote in The America We Deserve, “I’m going to shoot straight about terrorism and about the foreign threat.” Fair enough. That should start with a forceful restatement that border security is inseverable from defeating the criminal narco-insurgencies to our south. It could serve as a point of departure from which to articulate a “Trump Doctrine” on a counterinsurgency to defeat geographically proximate threats to American national and homeland security. Such a doctrine must address, honestly and resolutely, the causes of unauthorized migration toward the nation’s southwestern border. Mr. Trump (as well as Secretary Clinton) is on record acknowledging the insurgent nature of the threat and the urgency of responding to it. So now is the time to explicate the nature of that threat and to delineate a plan to defeat it.
There are proven templates from which to model such a counterinsurgency effort. The concept of scale is important because, as theorists like the French Army officer David Galula acknowledged, insurgencies usually begin small, often at the level of a street gang without national-scale political ambitions. The Mexican and Northern Triangle narco-insurgencies are “commercialist” in Bard O’Neill’s typology: “Their main aim appears to be nothing more than the acquisition of material resources through seizure and control of political power. They consider political legitimacy to be relatively unimportant. Coercive power is what counts.” They are solely focused on profits gained from criminal activity. What distinguishes narco-insurgencies is that they seek political influence and power not as an end but as a means to achieve economic profits and its determiners e.g., protection from rivals and from governmental reprisals. For commercialist insurgencies, this means controlling territory through which their critical logistics and communications lines run.
Counterinsurgency is not law enforcement. Paraphrasing John Maier, techniques that work best for law enforcement are ill suited to fighting criminal narco-insurgencies, which inflict violence within Mexico and the Northern Triangle at levels that jeopardize the existence of civil society and government at large there. Effective methods to clear insurgents from a populace are no mystery: Colonel Trinquier detailed one such method several decades ago. Nor are the narco-insurgencies’ weaknesses unknown: U.S. Army Field Manual 3-24 lists eight of them.
Of equal if not greater importance, the recent experience in Syria demonstrates (if any such demonstration is required) the necessity of protecting vulnerable populations in place. A core principle of the counterinsurgency theories developed by Trinquier and Galula, is this: that the counterinsurgent’s power should primarily be employed to protect the civilian population rather than chasing down insurgent forces. Galula went so far as to argue that the shift from offensive to defensive played to the counterinsurgent’s strengths. Again, there are tested methods for protecting noncombatant populations.
The protection of vulnerable populations cannot be delinked from offensive counterinsurgency if either is to succeed. Offensive counterinsurgency without protecting vulnerable populations would do little to abate unauthorized migration from regions under the effective control of narco-insurgents. It would likely strand migrants somewhere short of their objective, creating a refugee crisis of the type (though hopefully not the scale) witnessed in the Middle East and now in Europe.
Likewise, well-meaning efforts to relocate vulnerable populations en masse invite failure. In January 2016, the Obama administration announced it would work with the United Nations High Commissioner for Refugees (UNHCR) to allow persons facing persecution to apply for refugee status and resettlement from Central America. The initiative significantly widens the administration’s refugee policy response, which had been limited to an in-country refugee processing program established in December 2014 for certain minors in Honduras, El Salvador, and Guatemala whose parents are already in the United States. Relatively few applicants have been processed and brought to the United States so far through these in-country programs. Under the new plan, refugee processing centers open to adults will be established in countries outside the Northern Triangle. However well meaning, it is simply an attempt to stop unauthorized migrants short of the United States’ border and hold them in place without a defined endpoint.
“Transnational criminal network…are efficient, adaptive, innovative, and exceptionally ruthless. They will transport anything or anyone—cocaine, heroin, weapons, people, even wildlife—if they believe the potential profit is greater than the potential risk.” -ADM Kurt W. Tidd, USN (2016), Commander USSOCOM
Narco-insurgents within Mexico and the Northern Triangle have evolved over the past decade in ways that have made them far more sophisticated and dangerous than traditional criminal smugglers. Employing cadres of military-trained personnel equipped with sophisticated weaponry, today’s cartels carry out exceptionally complex operations, and apply force sufficient to overwhelm the response capacity of civilian law enforcement agencies.
We know from experience these situations quickly spiral. In the 1990s, the Revolutionary Armed Forces of Colombia (FARC) used the approximately $380 million it garnered from the drug trade each year to acquire advanced weapons and entice new recruits. By 2000, the FARC boasted around 20,000 combatants, was able to overwhelm and annihilate isolated army garrisons, had Bogota nearly cut off from the rest of the country, and controlled roughly 40 percent of Colombian territory.
One non-obvious threat to the United States comes from the fact that extreme rivalry among various Mexican drug cartels for regional control of the drug trade market has yielded an arms race. One among many examples serves to illustrate the point. In April 2016, agents of the Chihuahua State Attorney General (Fiscalía General del Estado) seized a large cache of weapons and protective equipment in the city of Nuevo Casas Grandes located in northwestern Chihuahua. The raid targeted La Línea (“The Line”) operations in Chihuahua, where the armed enforcer unit is an element of the larger Grupo Bravo de Nuevo Cártel de Juárez, which is active in the Juarez-El Paso drug trafficking corridor.
Among the weapons seized in the raid was a FIM-43 REDEYE, the man-portable air defense system (MANPAD) first issued to United States combat forces in 1967. Designed to destroy low-flying aircraft by homing on the heat of an aircraft engine, the FIM-43 can be made ready in seconds to fire its REDEYE surface-to-air missile (the name comes from the infrared sensor in the missile’s nose) and requires little training to use. There are also reports that Mexican drug cartels are commissioning custom-made unmanned aerial vehicles (UAV) or “drones” to transport narcotics across the Mexico-United States border.
“Experts are always on the defensive—and for good reason. They’re wrong so often.” -Donald J. Trump
That line is from Mr. Trump’s 2000 book, The America We Deserve. It is a useful reminder that much of what is written and said about border security is nonsensical. This includes some of what comes from the United States government, as Edward Alden and Bryan Roberts observed in their 2011 Foreign Affairs commentary:
“[T]he Department of Homeland Security has never clearly defined what border control means in practice. A secure border cannot mean one with no illegal crossings—that would be unrealistic for almost any country, especially one as big and as open as the United States. On the other hand, the borders cannot be considered secure if many of those attempting to enter illegally succeed. Defining a sensible middle ground, where border enforcement and other programs discourage many illegal crossings and most of those who try to cross illegally are apprehended, is the challenge.”
“Unfortunately, the U.S. government has failed to develop good measures for fixing goals and determining progress toward them. Since 2005, the DHS has reported how many miles of the country’s land borders are under its ‘operational control,’ but it has done so without having clearly defined what that standard means and without providing hard data to back it up. The lack of sound measurement has left the administration touting its efforts rather than their results…”
Set aside for a moment the Department of Homeland Security—a governmental agency charged with preventing the entry of terrorists, securing the borders, and carrying out immigration enforcement functions—stating insouciantly that it lacked “operational control” over the United States-Mexico border. A “secure border” is one that embodies the principles of physical prevention, approach and breach detection, and defense-in-depth to create a robust barrier to illegal crossings, the incidence of which would be exceedingly low, and trigger immediate response and interdiction by secondary defenses. A parallel principle is to deter unauthorized migration in the first place by protecting at-risk populations in situ and actively attacking the factors that cause it.
A secure border is a matter of national defense; border security failures are a matter of homeland security. Thus the “Countering Transnational Organized Crime” mission of the United States Southern Command:
“Illicit trafficking networks pose complex transnational threats to the stability of Latin America and the Caribbean and to U.S. public health and national security. Well-resourced organized crime groups move drugs, weapons, counterfeit items, money and people on these networks. This insidious web of crime threatens citizen security, undermines basic human rights, cripples the rule of law through corruption, erodes good governance, and hinders economic development. 
There is no disagreement about the character of the threat. Mr. Trump’s likely Democrat opponent, former Secretary of State Clinton, framed it back in September 2010:
“[W]e face an increasing threat from a well-organized network, drug-trafficking threat that is, in some cases, morphing into or making common cause with what we would consider an insurgency, in Mexico and in Central America.”
Criminal narco-insurgencies have turned large territorial expanses of the Northern Triangle and Mexico into ungoverned spaces. The laudable efforts of the United States Southern Command and its partners to combat these insurgencies are hamstrung by several factors, including the insistence of much of the United States government that the insurgencies are a law enforcement challenge, not a national security threat. As General Barry McCaffrey famously said several years back, “The ‘war on drugs’ is nonsense. If there was a war on drugs, you would have a general in charge.”
It may be the case that unauthorized migration has received almost unceasing attention because it is easier to rail about effects than to address causes. In large part, criminal narco-insurgencies operating in our nearest neighboring counties to the south collectively are such a root cause. But it is impossible to discuss United States action to debilitate and destroy them without taking into account the legacy of United States’ interventions in Mexico and Central America.
Though often tagged (incorrectly) as “isolationist,” the America First Committee was untroubled by this legacy. Its national chairman, retired General Robert E. Wood, made that abundantly clear in a 1940 speech on foreign policy:
“And while I think we should try in every way to maintain the friendship of our neighbors to the South, I think we should also make it clearly understood that no government in Mexico, Central America and the Caribbean South American countries will be tolerated unless it is friendly to the United States and that, if necessary, we are prepared to use force to attain that object.”
Mr. Trump asserts forcefully that Mexico is not, in General Wood’s phrase, “friendly to the United States.” He wrote last year, “I actually have a theory that Mexico is sending the absolute worse, possibly including prisoners, in order for us to bear the cost, both financial and social. That would account for the fact that there is so much crime and violence.” He follows that problematic claim one page later with a trenchant and informed argument about the threat posed by MS-13. While the apparent disconnect between speculation and analysis is puzzling, his consonance with General Wood’s perspective seems palpable.
No workable case for a border wall can be made in isolation. It is an instrument to stop an effect—unauthorized migration—rather than its causes. Nor is building an impermeable, son-of-Morice Line border wall from Tijuana 1,989 miles east to Brownsville practicable under any reasonable scenario. None of this says there is no case for border walls, as Israel and more recently, Hungary, have demonstrated, though at an appreciable political cost.
Josh Earnest, who at the time was President Obama’s Deputy Principal Press Secretary, said in June 2013:
“Now, the thing that I want to make clear is that the top priority of the President of the United States is the national security of the United States and protecting this homeland. And we need to make sure that we have the tools we need to confront the threat posed by terrorists, to disrupt plots that may exist, and to otherwise protect the homeland.”
About such tools, Mr. Trump wrote in 2000, “The question isn’t whether such a defense can be built. The question is whether it is the right defense for our time.” “The first line of defense,” he continued, “is to try to understand the nature of the threat.”
So today’s question is not whether a border wall of some configuration can be built: it can. The question is whether as border wall is the right defense. It may well be an element of the right defense, but it is certainly not the only one, nor necessarily the best one. The right defense depends, as Mr. Trump observed, on the nature of the threat. Unauthorized migration resolutely isnot that threat. That threat is the criminal narco-insurgencies that have seized political and geographic terrain in parts of Mexico and large swathes of the Northern Triangle, and established a dangerous and expanding presence inside the United States. With apologies to Mr. Earnest, the President’s job is not to disrupt plots by these insurgencies. It is to disrupt, disable, destroy and eradicate the insurgencies themselves. At the same time, it is the President’s duty, indeed the nation’s duty, to use American force to protect vulnerable peoples on our doorstep. If the America First Committee got anything right, it is this: that “Humanitarian aid is the duty of a strong, free country…to keep alive their hope for the return of better days.”
The translation of all source material is by the author unless noted otherwise.
 Breitbart [published online 10 November 2015]. https://www.breitbart.com/video/2015/11/10/watch-donald-trump-and-john-kasich-battle-over-immigration/. Last accessed 6 May 2016.
 In a July 2004 advisory opinion “Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory,” the International Court of Justice insisted on the term “the wall” calling it “the term which the General Assembly has chosen to use and which is also used in the Opinion, since the other expressions sometimes employed are no more accurate if understood in the physical sense…” See: https://www.icj-cij.org/docket/index.php?pr=71&p1=3&p2=1&case=131&p3=6. Last accessed 5 May 2016.
 See: https://www.securityfence.mod.gov.il/Pages/ENG/operational.htm. Last accessed 6 May 2016.
 See: https://www.ontheissues.org/Archive/2015_Fox_GOP_Donald_Trump.htm. Last accessed 6 May 2016.
 Author’s note: It is the movement of persons and contraband toward the border of the United States that is of interest here, since the purpose of a border wall is to deter, and failing that, to exclude such movement. So our interest in assessing the utility of a border wall is with unauthorized migration (and the movement of contraband) toward the United States, where by contrast, an “illegal immigrant” has by definition already entered into the United States illicitly.
 The social science literature is replete with findings that support this claim. A 2011 study concluded, “[I]n situations characterized by high levels of violence people see no option but leaving. Under conditions of extreme violence, threats to safety are perceived to exceed the risks of travel to a new and unfamiliar destination.” Pratikshya Bohra-Mishra & Douglas S. Massey (2011). “Individual Decisions to Migrate During Civil Conflict.” Demography. 48(2), 401–424. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3365856/. Last accessed 10 May 2016.
 It is also worth noting that changes in the number of unauthorized immigrants in the United States are driven by many factors. For example, social scientists have demonstrated the common sense argument that unauthorized immigration increases when the American economy is expanding, and decreases when it is contracting. See: Wayne A. Cornelius, Scott Borger, Adam Sawyer, David Keyes, Clare Appleby, Kristen Parks, Gabriel Lozada & Jonathan Hicken (2008). “Controlling Unauthorized Immigration from Mexico: The Failure of “Prevention through Deterrence” and the Need for Comprehensive Reform.” Published by the Center for Comparative Immigration Studies (CCIS) University of California—San Diego. https://www.immigrationpolicy.org/sites/default/files/docs/CCISbriefing061008.pdf#page=5. Last accessed 6 May 2016.
 One of the four principles of the America First movement adopted at its founding at Yale University in 1939. See Wayne S. Cole (1953). America First: The Battle Against Intervention 1940-1941 (Madison: University of Wisconsin Press) 11.
 In March 1951, the America First Committee stated as one of its five principles “We must build a defense, for out own shores, so strong that no foreign power or combination of powers can invade our country, by sea, air or land.” See: America First Committee (1941). America First Committee Bulletins 140 and 140A (20 March 1941).
 The 2015 Fragile State Index places Guatemala at a “High Warning” and El Salvador, Honduras, Mexico, and Nicaragua at a “Warning” of state fragility, which incorporates a wide range of state failure risk elements. See: https://fsi.fundforpeace.org. Last accessed 11 May 2016.
 “Plan of the Alliance for Prosperity in the Northern Triangle: A Road Map.” Regional Plan Prepared by El Salvador, Guatemala and Honduras dated September 2014, 1. https://idbdocs.iadb.org/wsdocs/getdocument.aspx?docnum=39224238 . Last accessed 8 May 2016. The reports adds “Most of them were males and females aged 15 to 30 seeking work that would provide them with a higher standard of living and greater opportunities for their children.”
 Council on Foreign Relations (2016). “Central America’s Violent Northern Triangle.” CFR Backgrounders report dated 19 January 2016. https://www.cfr.org/transnational-crime/central-americas-violent-northern-triangle/p37286. Last accessed 7 May 2016. Reliable contemporary data on the number and country of origin of unauthorized migrants attempting to enter the United States are hard to come by, given that open-access governmental data for the most part lags by four or five years. That being said, however, United States Border Patrol apprehension data indicates that most (detected) unauthorized migration comes from Mexico and the Northern Triangle.
 John Sullivan & Adam Elkus (2009). “Red Teaming Criminal Insurgency.” Red Team Journal [published online 30 January 2009]. https://redteamjournal.com/2009/01/red-teaming-criminal-insurgency-1/. Last accessed 12 May 2016.
 An ancient strategy, it was formalized for modern counterinsurgency by a French Army officer, Roger Trinquier, though he did not call it by that name. [Trinquier (1985; 1964). Modern Warfare: A French View of Counterinsurgency Daniel Lee, Trans. (Fort Leavenworth, KS: U.S. Army Command and Staff College). https://louisville.edu/armyrotc/files/Roger%20Trinquier%20-%20Modern%20Warfare.pdf. Last accessed 10 May 2016] The term “ink blot” was coined in the late the 19th century by another French Army officer, Marshal Louis Lyautey, who applied the concept in Madagascar and Morocco. In 1906, Lyautey and another French Army officer, Henri Gallieni, were instrumental in establishing the Ecole Militaire Spécialisée dans l’outre—Mer et l’etranger, a school devoted to integrating the study of foreign cultures into training for officers deploying to theaters of irregular war. [Colonel Henri Boré (2009). “Complex Operations in Africa: Operational Culture Training in the French Army. Military Review (March-April 2009) 65-71]
The United States adopted an inkblot variant during the Vietnam War. Assistant Secretary of State for Far Eastern Affairs, Roger Hilsman—who doubled as Director of the Department’s Bureau of Intelligence and Research—in November 1961 oversaw a study entitled “Internal Warfare and Security of the Underdeveloped States.” In February 1962, Hilsman authored a strategic concept for Vietnam, integral to which was the Strategic Hamlet Program, which Hilsman envisioned gradually extending throughout the countryside like an inkblot. [“The Battle for Hearts and Minds: Counterinsurgency and Reconstruction Programs in Vietnam
East Auditorium” 30 September 2010. https://history.state.gov/conferences/2010-southeast-asia/battle-for-hearts-and-minds. Last accessed 10 May 2016].
 While Mexican nationals are smuggled along the full length of the Mexican border, unauthorized migrants from the Northern Triangle tend to follow eastern routes along the Caribbean and Gulf of Mexico coastline toward crossing points along the Texas border. One reason is a United States’ policy to release unauthorized migrants on their own recognizance when shelter space is overwhelmed, as occurs frequently at the Rio Grande Valley and Del Rio border stations. [United Nations Office on Drugs and Crime (2012). Transnational Organized Crime in Central America and the Caribbean: A Threat Assessment (Vienna: UNODC) 48] More recently, unauthorized migrants from the Northern Triangle have shifted towards Arizona and away from the Rio Grande Valley in order to avoid transiting parts of northern Mexico in which the fearsome Los Zetas crime syndicate is active. It started not as a territorial group but as an enforcer gang for the Gulf Cartel., composed mostly of former Special Forces operatives. Eventually, Los Zetas broke away from the Gulf Cartel to become a cartel in its own right, launching an offensive that would see them expand throughout Mexico and Guatemala. Today, however, it is an increasingly fragmented force dependent on local criminal revenues. [https://www.insightcrime.org/mexico-organized-crime-news/zetas-profile. Last accessed 5 May 2016] Los Zetas moved into Guatemala before it split from the Gulf Cartel, beginning in 2005 by recruiting Guatemalan special force soldiers (kaibilies) and then establishing a local chapter in 2008.
 GEN John F. Kelly, USMC (2015). “Posture Statement of General John F. Kelly, United States Marine Corps Commander, United States Southern Command, before the 114th Congress Senate Armed Services Committee 12 March 2015,” 3. https://www.southcom.mil/newsroom/Documents/SOUTHCOM_POSTURE_STATEMENT_FINAL_2015.pdf. Last accessed 7 May 2016.
 Guatemala, Central America’s most populous country, endured a 36-year internal armed conflict that claimed roughly 200,000 thousand lives, and ingrained a pervasive culture of fear and violence, especially among members of the country’s majority indigenous population.
 Javier Q. Meléndez, Roberto B. Orozco, Sergio M. Moya & Miguel R. López (2010). Una Aproximación a la Problemática de la Criminalidad Organizada en las Comunidades del Caribe y de Fronteras (Managua, Nicaragua: Instituto de Estudios Estratégicos y Políticas Públicas) 14-16.
 Testimony of Ambassador Luis E. Arreaga, Deputy Assistant Secretary Of State, Bureau Of Inter-National Narcotics And Law Enforcement Affairs, before the United States House of Representatives subcommittee on Coast Guard and Maritime Transportation of the Committee on Transportation and Infrastructure, and the subcommittee on the Western Hemisphere of the Committee on Foreign Affairs (29 April 2014), 10.
 Ralph Espach & Daniel Haering (2012). Border Insecurity in Central America’s Northern Triangle (Washington, D.C.: Migration Policy Institute) 3.
 Some like OAS Secretary General Jose Miguel Insulza praised the truce for reducing El Salvador’s homicide rate (reportedly from 14.0/day to 5.5/day although United States law enforcement could not verify those figures) and starting on the pathway toward a long-term solution to violence and criminality. However, while gang leaders pledged various concessions (e.g., not to forcibly recruit children into their ranks or perpetrate violence against women; to turn in small amounts of weapons; and to engage in broader negotiations) they never surrendered control of their respective territories. This led critics like El Salvador’s Minister of Justice & Public Security and Attorney General to point out that while gang-on-gang homicides may have declined, extortion and other violent crimes did not. Moreover, there is the question of recognizing the gangs as legitimate political actors and acceding to their demands, especially since El Salvador’s maras emerged more powerful and better organized after the truce collapsed, largely as a function of less restrictive prison conditions.
Maras is short for marabuntas, a deadly species of army ant.
 Both MS-13 and M-18 were founded in Los Angeles immigrant communities. The larger MS-13’s roots are Salvadoran while M-18’s are Mexican (its El Salvadoran branch split in 2005 into two factions, one of which is known as the Revolutionarios and the other as Mara 18). The United States government designated MS-13 a “transnational criminal organization” in October 2012, the first such designation for a domestic street gang. In California, M-18 has a close relationship with the Mexican Mafia (aka “La M”), a street gang with a strong presence in United States federal prisons.
 Donald J. Trump (2015). Make America Great Again. Kindle edition, 135.
 Gang membership is divided between M-18 and MS-13 as follows: 17,000 and 5,000 in El Salvador; 5,000 and 7,000 in Honduras; and 8,000 and 12,000 in Guatemala. Source: United Nations Office on Drugs and Crime (2012). Transnational Organized Crime in Central America and the Caribbean: a Threat Assessment.
 See: United States State Department (2012). “Gangs, Youth, and Drugs – Breaking the Cycle of Violence.” Remarks by William R. Brownfield, Assistant Secretary, Bureau of International Narcotics and Law Enforcement Affairs, at the Institute of the Americas. Press release dated 1 October 2012. See also: United Nations Office on Drugs and Crime (2012), op cit., 29.
 El Salvador suffered a brutal civil war that ran from 1980 to 1992, during which some 75,000 people were killed and 1 million were displaced in a country of only 5 million. The war was fought between the conservative government and the leftist Farabundo Marti National Liberation Front, with numerous human rights violations committed by both sides
 In Guatemala, leftist rebels and various military-led or -backed governments fought a civil war from 1960 until the signing of a peace treaty in 1996. Over 200,000 Guatemalans were killed, most (83%) of Mayan descent. The military and state-sponsored forces—some members of which themselves moved into drug trafficking—were accused of committing numerous human rights violations.
 This argument is based in part on the number of deportations from the United States during the three-year period 2010-2012 and the percentage of the deportations represented by persons who were deported on criminal grounds.
Source: Congressional Research Service (2014). Gangs in Central America, 7. https://www.fas.org/sgp/crs/row/RL34112.pdf. Last accessed 5 May 2016.
 Steven Boraz (2007). “Case Study: The Guatemala-Chiapas Border.” In Angel Rabasa, Steven Boraz, Peter Chalk, Kim Cragin, Theodore W. Karasik, Jennifer D.P. Moroney, Kevin A. O’Brien & John E. Peters. Ungoverned Territories: Understanding and Reducing Terrorism Threats (Santa Monica, CA: RAND Project Air Force) 277
 Migration Policy Institute (2016). “Increased Central American Migration to the United States May Prove an Enduring Phenomenon” [published online 16 February 2016]. https://www.migrationpolicy.org/article/increased-central-american-migration-united-states-may-prove-enduring-phenomenon. Last accessed 10 May 2016.
 Posture Statement of Admiral Kurt W. Tidd, Commander, United States Southern Command before the 114th Congress Senate Armed Services Committee (10 March 2016), 7. https://www.southcom.mil/newsroom/Documents/SOUTHCOM_POSTURE_STATEMENT_FINAL_2016.pdf. Last accessed 10 May 2016.
 Donald J. Trump (2000). The America We Deserve. Kindle edition.
 Department of the Army (2006). Field Manual 3-24 Counterinsurgency. (Washington, D.C.: Headquarters, Department of the Army) 1-18. https://usacac.army.mil/cac2/Repository/Materials/COIN-FM3-24.pdf. Last accessed 9 May 2016.
 Generally speaking, pedestrian fence is located in urban areas and adjacent to ports of entry, whereas vehicle fence is located in relatively unpopulated and remote areas of the border.
 Paul Staniland (2005). “Defeating Transnational Insurgencies: The Best Offense is a Good Fence.” The Washington Quarterly. 29:1, 21-40. https://www.mafhoum.com/press9/264P2.pdf. Last accessed 10 May 2016.
 Edgar O’Ballance (1967). The Algerian Insurrection, 1954-62 (Hamden: Archon Books) 92.
 Bard E. O’Neill (2005). Insurgency and Terrorism: From Revolution to Apocalypse, 2nd ed. (Washington, D.C.: Potomac Books) 20. Dr. O’Neill is a former Air Force officer and Professor of International Affairs at the National War College, where he is Director of Studies of Internal Warfare and Terrorism.
 John Maier (2013). ” Applying Counterinsurgency Doctrine as a Strategy to Defeat the Mexican Cartels.” Small Wars Journal [published online 27 October 2013]. https://smallwarsjournal.com/jrnl/art/applying-counterinsurgency-doctrine-as-a-strategy-to-defeat-the-mexican-cartels. Last accessed 13 May 2016. The author highly recommends LTC Maier’s authoritative journal article.
 Department of the Army (2006), op cit., 1-17.
 General David Petraeus, one author of United States Army’s Field Manual 3-244 Counterinsurgency wrote, “Of the many books that were influential in the writing of [FM] 3-24, perhaps none was as important as David Galula’s Counterinsurgency Warfare: Theory and Practice.” Galula also wrote a second influential book, Pacification in Algeria 1956-1958 (1963).
 Posture Statement of Admiral Kurt W. Tidd, Commander, United States Southern Command before the 114th Congress Senate Armed Services Committee 10 March 2016. https://www.southcom.mil/newsroom/Documents/SOUTHCOM_POSTURE_STATEMENT_FINAL_2016.pdf. Last accessed 10 May 2016.
 Christopher J. Curran (2015). “Spillover: Evolving Threats and Converging Legal Authorities in the Fight Against Mexican Drug Cartels.” Harvard National Security Journal. v.6, 347. https://harvardnsj.org/wp-content/uploads/2015/06/Curran.pdf. Last accessed 13 May 2016.
 Stephen P. Weiler (2004). Colombia: Gateway to Defeating Transnational Hell in the Western Hemisphere. (Carlisle, PA: U.S. Army War College) 3-4.
 Robert J. Bunker & Byron Ramirez, Eds. (2013). Narco Armor: Improvised Armored Fighting Vehicles in Mexico. (Fort Leavenworth, KS: The Foreign Military Studies Office) 4. https://scholarship.claremont.edu/cgi/viewcontent.cgi?article=1423&context=cgu_fac_pub. Last accessed 13 May 2016.
 El Nuevo Cártel de Juarez (NCDJ) is a Mexican drug cartel formerly known as the Cártel de Juárez (“Juárez Cartel”) and based in Ciudad Juárez, Chihuahua. Grupo Bravo is an armed wing of the NDCJ.
 REDEYE carried a conventional high explosive warhead. It was operational worldwide with the U.S. Army and U.S. Marine Corps for more than two decades until it was replaced during the 1980s in both services by the more capable STINGER missile system. Their size and weight makes the MANPAD easy to transport and to conceal, for example, in the trunk of an automobile.
 Robert J. Bunker (2014). Mexican Cartel Tactical Note #21. Small Wars Journal [published online 1 August 2014]. https://smallwarsjournal.com/blog/mexican-cartel-tactical-note-21. Last accessed 7 May 2016.
 Edward Alden & Bryan Roberts (2011). “Are U.S. Borders Secure?” Foreign Affairs [published online 16 June 2011]. https://www.foreignaffairs.com/articles/united-states/2011-06-16/are-us-borders-secure. Last accessed 10 May 2016.
 Congress required under the Secure Fence Act of 2006 that the entire border should be 100% operationally controlled by the Department of Homeland Security.
 https://www.southcom.mil/ourmissions/Pages/Countering%20Transnational%20Organized%20Crime.aspx. Last accessed 10 May 2016.
 It is true that some scholars dispute the “insurgency” characteristic on technical grounds, usually because it does not fully satisfy some chosen definition of that term. One of the better-argued examples of this is: CW4 Michael G. Rogan, USA (2011). “Is the Narco-violence in Mexico an Insurgency?” Monograph published by the School of Advanced Military Studies, United States Army Command and General Staff College, Fort Leavenworth, Kansas. https://www.hsdl.org/?view&did=721559. Last accessed 13 May 2016.
 “Mexico denies Hillary Clinton’s ‘insurgency’ comparison.” Christian Science Monitor [published online 9 September 2010]. https://www.csmonitor.com/World/terrorism-security/2010/0909/Mexico-denies-Hillary-Clinton-s-insurgency-comparison. Last accessed 10 May 2016.
 Brigadier General Robert E. Wood, USA Ret. (1940). “Our Foreign Policy.” Speech delivered before the Chicago Council on Foreign Relations, 4 October 1940. https://www.ibiblio.org/pha/policy/1940/1940-10-04a.html. Last accessed 13 May 2016. Author’s note: General Wood (b.1879 d.1969) served as national chairman of the America First Committee and the President of Sears Roebuck & Co. He retired from the United States Army in 1919 having served in the American Expeditionary Force in France and as the Army’s acting Quartermaster General.
 Trump (2015), op cit., 136. The basis for this “theory” is left unsaid.
 https://www.whitehouse.gov/the-press-office/2013/06/06/press-gaggle-deputy-principal-press-secretary-josh-earnest-and-secretary. Last accessed 13 May 2016.
 His context was the debate over missile defense, which he opposed on the basis that while possible, it misapprehended the source of the threat (which he suggested was miniaturized weapons).