I last saw Nuevo Laredo in late 2010, around 9pm on a humid autumn evening. I had just walked off a bus after a three hour ride from Monterrey, northern Mexico’s industrial and financial capital. For much of the previous two years, I had traveled through Mexico’s six northern states, researching the region’s geopolitics.  I traveled alone, and shoe leather worked best inside cities. The sights and smells made walking more interesting. Renting a car?  With bloqueos interrupting traffic whenever the cartels saw fit, only a fool would drive alone.  Busses were ideal for long transportation. Taxis covered everything in the middle.

At the Nuevo Laredo bus station, vehicles swarmed for preferred or prescheduled cargo.  Three squads of Mexican soldiers, tan ski masks pulled tight, snatched up four of their comrades in civilian clothes.  They had traveled with me on the bus, probably returning as a group from a few days leave to discourage kidnapping.  One was clearly in charge; most likely a senior sergeant.  Two were junior soldiers who carried Nextel phone/walkie-talkies, which squawked with news of a skirmish on the city outskirts.  The other soldier slept.  All four appeared oblivious to my presence.

My taxi driver drove fast, whizzing alongside military Humvees.  Police on every street corner brandished the FX-05 Xiuhcoatl Mexican assault rifle.  According to the cabbie, the Mexican Army soldiers had killed eight Zeta sicarios.  Nuevo Laredo was awash with rumors like that, but it was impossible to tell how many were true.  The violence was indiscriminate enough to make anything possible.  Media outlets received anonymous phone calls informing them of murders they were never allowed to mention.  Hundreds, perhaps thousands, had died or disappeared.  The latter was the same as the former.

The driver could not explain to me exactly what the Mexican military was trying to do in Nuevo Laredo.  The soldiers were certainly moving around with a sense of urgency.  Presumably, they were collecting intelligence; exploiting information; arresting or attacking targets.  But they seemed mostly to just be presenting a show of force; strutting like sculpted bodybuilders who looked good onstage but lacked functional muscle.  Their efforts were symbolized best by a humvee parked next to the Rio Grande, its 40mm grenade launcher locked and loaded.  What rules of engagement did the soldier have who was manning the turret gun?  Who exactly was he supposed to shoot at, since each round could never hit a pinpoint target?  What would a grenade explosion do for billions of dollars of trade legally streaming across the US-Mexico border?

With immigration reform leading President Obama’s legislative agenda, Americans are going through their periodic paroxysms over border security.  But as RAND’s Brian Michael Jenkins notes, both the United States and Mexico will likely downplay the drug violence and the cartel war in the coming year.  Like President Obama, Mexican President Enrique Peña Nieto has an ambitious domestic agenda, seeking to make his legacy on education and energy reform.  Also like Obama, Peña Nieto would prefer to declare victory quietly in his predecessor’s war, receiving political credit for the denouement of combat without suffering the political cost of its conduct.

So who will win in Nuevo Laredo?  Will the city ever return to its former tranquility, or are soldiers and police now a permanent fixture?  The Mexican government may declare victory, but only the cartels — who still control the monopoly of violence in Mexico — will have the final say.  Ironically, through their experiments with marijuana legalization, Americans may have a bigger and more enduring impact on Mexico’s drug war than the soldiers who patrolled Nuevo Laredo.  Whether it erodes or decreases the violence, U.S. state-level marijuana legalization will certainly have an impact.  We can only hope it’s more effective than the 40mm grenade launcher at reducing violence.