The Tet Offensive of 1968 proved to be the turning point of the Vietnam War and its effects were far-reaching. It changed the entire way that the United States approached the war: before the Tet Offensive the U.S. objective in Vietnam was to win the war; after the Tet Offensive, the U.S. objective shifted toward finding a face-saving way to get out of Vietnam.

To understand fully the impact of the 1968 Tet Offensive, we must first go back to the previous year. By 1967, after more than two years of bitter fighting, the commitment of more than 400,000 troops, and steadily increasing casualty figures, many Americans believed that the war had degenerated into a bloody stalemate. At the same time, the anti-war movement was increasing in volume and intensity. Politically, President Johnson was under fire even within his own party for his handling of the war.

Given this situation, Johnson launched what became known as the “success offensive,” designed to convince the American people that the war was being won and that administration policies were succeeding. Administration spokesmen fanned out and began to spread the word. As part of this effort, the President brought home General William Westmoreland, senior US commander in Vietnam, in mid-November 1967 to make the administration’s case.

Westmoreland was glad to do so. By his primary metric—the body count—the US and allied forces were making significant headway against the Viet Cong and the North Vietnamese Army on the battlefield, prevailing in every major battle and inflicting heavy casualties on the NVA and main force VC units. In a number of public and private venues, the general insisted that progress was being made in the war and that there was “a light at the end of the tunnel.” These words would come back to haunt him in a very short time.

Meanwhile, in Hanoi, even as Westmoreland spoke, the Central Committee of the Lao Dong Party was finalizing preparations for a country-wide offensive designed to break the stalemate and ‘liberate’ South Vietnam.

The decision to launch the offensive was the result of a long-standing internal struggle over military strategy within the leadership in Hanoi. These struggles were principally over the timing involved in shifting from a protracted war toward a more decisive approach. In the end, however, the more cautious proponents of protracted war were overcome by those like General Nguyen Chi Thanh, commander in the South, who advocated a nationwide general offensive.

Ironically, Thanh died before the decision was made to launch the offensive and the responsibility for preparing the plan for the offensive fell to General Vo Nguyen Giap. The plan he came up with was designed to ignite a general uprising among the people of South Vietnam, shatter the South Vietnamese armed forces, and topple the Saigon regime, while at the same time increasing the level of pain for the Americans by inflicting more casualties on U.S. forces. At the very least, the decision-makers in Hanoi hoped to position themselves for any follow-on negotiations that might take place in the wake of the offensive.

The preparations for the offensive began in the summer months of 1967; the target date for launching the offensive was the beginning of Tet, the lunar New Year holiday, which would come at the end of January 1968.

During the second half of 1967, in what we would today call “shaping operations,” the Communists launched a number of attacks to draw US and allied attention away from the population centers, which would be the ultimate objectives for the 1968 offensive. As part of this effort, NVA forces engaged the Marines in a series of sharp battles in the hills surrounding Khe Sanh, a base in western Thua Thien Province, south of the DMZ up against the Laotian border. Further to the east, additional NVA forces besieged the Marine base at Con Thien just south of the Demilitarized Zone.  Further south, Communist forces attacked Loc Ninh and Song Be, both in III Corps Tactical Zone, and in November they struck U.S. forces at Dak To in the Central Highlands. In purely tactical terms, these “border battles” as they became known, were costly failures for the Communists and they no doubt lost some of their best troops; they sustained over 300 killed at Dak To alone. However, at the operational level, these battles achieved the intent of Giap’s plan by diverting General Westmoreland’s attention to the outlying areas away from the buildup around the urban target areas that would be struck during the Tet attacks.

US military intelligence analysts knew that the other side was planning some kind of large-scale attack in 1968, but they did not believe that it would come during Tet or that it would be countrywide. Still, there were many indicators that the enemy was planning something. When new intelligence poured in from all four Corps Tactical Zones, Westmoreland and his staff came to the conclusion that a major enemy effort was probable—all signs pointed to a new offensive. Still, most of the significant enemy activity had been along the DMZ and in the remote border areas.

In the words of one official in the Johnson White House, writing later in 1968, the Tet Offensive represented “the worst intelligence failure of the war.” Many historians and other observers have endeavored to understand how the Communists were able to achieve such a stunning level of surprise. There are a number of possible explanations, but there are two main reasons for the failure to predict what was coming. First, Allied estimates of enemy troop strengths and intentions were flawed. Part of the problem was that in the fall of 1967, Headquarters MACV in Saigon, in the face of vigorous disagreement from the Central Intelligence Agency, changed the way it calculated enemy order of battle—in terms of strength and organization for combat. At Westmoreland’s direction, the military analysts decided not to count the local militias of the National Liberation Front in the enemy order of battle, instantly reducing estimated enemy strength downward from 300,000 to 235,000. Almost overnight, this seemed to indicate that the war was going better than it was, but at the same time discounted a large number of potentially effective enemy fighters and support personnel. Having revised their enemy estimates, it appears that US military intelligence analysts then apparently accepted those estimates at face value—as ground truth—this is tantamount to what is known in some military circles as “drinking your own bath water.”

This caused Westmoreland and his analysts to discount any intelligence indicators that ran counter to the assessment that the enemy was getting weaker and, they reasoned, that any new offensive, because of this overall weakness, would be localized and limited. Thus, when incoming intelligence reports indicated that the enemy was planning a country-wide offensive, the reports were largely ignored.

The second major reason for the failure to predict the size and scope of the coming offensive was the focus on Khe Sanh. In late December 1967, signals intelligence indicated that there was a significant enemy build-up in the Khe Sanh area, site of the earlier “Hill Fights” in western Thua Thien Province. Westmoreland and his intelligence analysts decided that this build-up signified that the enemy’s main effort in 1968 would come at Khe Sanh. Therefore, Westmoreland, his headquarters, and the White House turned their focus on Khe Sanh and the northernmost provinces.

On 21 January, the North Vietnamese Army began the first large-scale shelling of Khe Sanh, which was followed by renewed heavy fighting in the hills surrounding the Marine base. These attacks seemed to confirm Westmoreland’s earlier assessment that the remote Marine base would be the focal point for any new Communist attack. He was sure that this was the opening salvo of the anticipated enemy offensive. The fact that the Khe Sanh situation looked hauntingly similar to that which the French had faced when they were decisively defeated at Dien Bien Phu in 1954 only added increased urgency to the events unfolding there.

Accordingly, Westmoreland ordered the commencement of Operation Niagara, a massive bombing campaign focused on suspected enemy positions around Khe Sanh. Additionally, he ordered the 1st Cavalry Division from the Central Highlands to Phu Bai just south of Hue and one brigade of the 101st Airborne Division to I Corps to strengthen the defenses of the northernmost provinces. By the end of January, more than half of all US combat maneuver battalions were in the I Corps area.

For the reasons just stated, when the Communists launched the Tet Offensive, they achieved almost total surprise. It could have been worse—due to a failure in coordination, a number of enemy attacks were launched prematurely in the Central Highlands and the adjacent coastal plains, during the early morning hours of 30 Jan—this was due to the fact that they were using a different lunar calendar than the main force, which was off by 24 hours. These premature attacks provided at least some warning for U.S. forces, but it was too late in most cases for the South Vietnamese forces, because most of the ARVN soldiers were home on leave and could not be recalled in time to stop what was to come the next night.

In the early morning hours of 31 January, the combined forces of the Viet Cong and the North Vietnamese Army, a total of over 84,000 troops, struck with a fury that was breathtaking in both its scope and suddenness. In attacks that ranged from the DMZ all the way south to the tip of the Ca Mau Peninsula, the NVA and VC struck 36 of South Vietnam’s 44 province capitals, 5 of its 6 largest cities, 71 of 242 district capitals, and virtually every allied airfield and key military installation in the country. One American general at the time said the situation map depicting the attacks “lit up like a pinball machine.”

In one of the most spectacular attacks, 19 VC sappers conducted a daring raid on the US Embassy in Saigon. Elsewhere in Saigon, VC units hit Tan Son Nhut Air Base, the South Vietnamese Joint General Staff headquarters, and a number of other key installations across the city. Some of the bitterest fighting was in Cholon, the Chinese section of Saigon.

Far to the north, 7500 VC and North Vietnamese soldiers overran and occupied Hue, the ancient imperial capital. Marines and ARVN soldiers had to be sent in to retake the city in almost a month of bitter house-to-house fighting.

The attacks of the Tet Offensive that raged up and down the length and breadth of South Vietnam were unprecedented in their magnitude and ferocity and the reports streaming in from Saigon portrayed the bitter fighting in near real-time on the evening news on the three TV networks.

CBS television news anchor Walter Cronkite, who had witnessed firsthand the bitter fighting at Hue, no doubt voiced the sentiment of many Americans when he exclaimed, “What the hell is going on?—I thought we were winning the war.” On 27 Feb, after returning from Vietnam, Cronkite went on the air, and declared the war a stalemate, and called for the U.S. to negotiate its way out of the war.

In truth, the Tet Offensive, as it unfolded during the next weeks and months, turned out to be a disaster for the Communists, at least at the tactical level. While the North Vietnamese and Viet Cong enjoyed initial successes with their surprise attacks, allied forces quickly overcame their initial shock and responded rapidly and forcefully, driving back the enemy in most areas. The first surge of the initial phase of the offensive was over by the end of February and most of these battles were over in a few days. There were, however, a few notable exceptions—fighting continued to rage in the Chinese section of Saigon, at Hue, and also at Khe Sanh—battles in which the allies eventually prevailed as well.

In the end, allied forces used superior mobility and firepower to rout the enemy troops, who failed to hold any of their military objectives. Additionally, the South Vietnamese troops, rather than fold, as the North Vietnamese had expected, acquitted themselves reasonably well. As for the much anticipated general uprising of the South Vietnamese populace, it never materialized.

During the bitter fighting that extended into the fall, the Communists sustained staggering casualties. Conservative estimates put their losses at more than 40,000 killed in action with an additional 7,000 captured. By September, when the subsequent phases of the offensive had run their course, the Viet Cong, who had borne the brunt of the heaviest fighting in the cities, had been dealt a significant blow from which they never really recovered; the major fighting for the rest of the war would be done by the North Vietnamese Army from late 1969 until the end of the war.

The casualty figures during Tet for the allied forces were much lower, but they were still high. On 18 February, MACV posted the highest US casualty figure for a single week during the entire war—543 killed and 2,500 wounded. Total U.S. killed in action figures for the period February to March, 1968, were over a thousand. These casualty figures continued to mount as subsequent phases of the offensive extended into the fall. By the end of the year, U.S. killed in action for 1968 totaled more than 15,000.

Allied losses combined with the sheer scope and ferocity of the offensive and the vivid images of the savage fighting on the nightly TV news stunned the American people, who were astonished that the enemy was capable of such an effort. Their president and the senior US general in Vietnam had told them only two months before that the enemy was on its last legs and that the war was near an end. The intense and disturbing scenes depicted on the nightly TV news told a different story—a situation which added greatly to the growing credibility gap between the people and the administration. Having accepted the administration’s optimistic reports, but now confronted with a different reality, many Americans concluded that we were losing or at best locked in a bloody stalemate with no end in sight.

The Tet Offensive also had a major impact on Lyndon Johnson, who was visibly shaken by the turn of events. Although General Westmoreland rightfully claimed a great victory in the heavy fighting that continued into the fall of 1968, Johnson, like the American people, was stunned by the ability of the Communists to launch such wide-spread attacks. When Westmoreland, urged on by Chairman of the Joint Chiefs, General Earle Wheeler, asked for 206,000 troops to “take advantage of the situation,” the president balked and began to consider alternative courses of action.

Johnson turned to a group of unofficial advisors known as the “Wise Men.” This was a group of senior statesmen and retired generals to whom he had turned in the past for advice and support. He had met with them in mid-1967 and they recommended that he stay the course in Vietnam. However, when he convened the group in March 1968, they almost unanimously recommended that he find a way to disengage from the war in Vietnam. Stunned by this reversal, Johnson charged Clark Clifford, who had replaced Robert McNamara as Secretary of Defense, to conduct a study to determine the way ahead in Vietnam.

In a very real sense, the Tet Offensive fractured the administration’s “shakey” consensus on the conduct of the war and the reassessment that Johnson ordered permitted the airing of new alternatives. The civilians in the Pentagon recommended that allied efforts focus on population security and that the South Vietnamese be forced to assume more responsibility for the fighting while the US pursued a negotiated settlement. The Joint Chiefs of Staff, not surprisingly, took exception to this approach and recommended that Westmoreland be given the troops that he had asked for and be permitted to pursue enemy forces into Laos and Cambodia.

While the way ahead was being debated within the administration, public opinion polls on the President’s handling of the war continued to spiral downward. In the New Hampshire democratic primary, Johnson barely defeated challenger Senator Eugene McCarthy, winning by only 300 votes—a situation which convinced Robert Kennedy to enter the presidential race as an antiwar candidate.

Beset politically by challengers within his own party and seemingly still in shock from the spectacular Tet attacks, on 31 March, Johnson went on national television to address the nation. He then stunned the audience by announcing that he would not run for re-election—The Tet Offensive had claimed its most important victim—the sitting president of the United States.

In the aftermath of Johnson’s announcement, chaos reigned at the Democratic National Convention in downtown Chicago. Eventually, Vice President Hubert Humphrey won the democratic nomination. The following November, Richard Nixon won the presidential election and began the long U.S. bloody withdrawal from Vietnam.

In summary, The Tet Offensive of 1968 was a turning point in the war in Vietnam. Westmoreland and other senior officials were blinded to the indications that a countrywide offensive was imminent because these indications did not conform to their preconceived notions about enemy capabilities and allied progress in the war. Even after the offensive was launched, the initial reaction at Westmoreland’s headquarters was to place the attacks within the framework of those notions, seeing them as diversionary actions meant to focus attention away from what was seen as the main objective—the Marine base at Khe Sanh. Thus, MACV was not prepared when the enemy offensive was launched.

In the case of the Tet Offensive, intelligence became an extension of Westmoreland’s optimism and LBJ’s need to show progress—not an accurate reflection of the enemy’s capabilities. This set the stage for the impact of the enemy’s surprise attacks in Tet 1968. Johnson and Westmoreland built a set of expectations – false, as it turned out — about the situation in Vietnam in order to win public support for the administration’s handling of the war and dampen antiwar sentiment. These expectations, based on severely flawed intelligence, played a major role in the stunning impact of the Tet Offensive. When the Tet Offensive exploded on 30-31 January, the resulting loss of credibility for the president and the military high command in Saigon was devastating. At that point, the fact that the allied forces had prevailed in 1968 was rendered irrevelant.

The images and news stories of the bitter fighting seemed to put the lie to the administration’s claims of progress in the war and stretched the credibility gap to the breaking point. The tactical victory thus became a strategic defeat for the United States, convincing many Americans that the war was unwinnable. It effectively toppled an American president, convinced the new president to “Vietnamize” the war, led to U.S. disengagement from the war, and paved the way for the ultimate triumph of the Communists in 1975.