U.S. troops had been at war with North Vietnamese soldiers and guerrilla fighters for almost three years as of early 1968.
It had been jungle warfare, with small U.S. and South Vietnamese units mostly conducting search-and-destroy missions, often under dense forest canopies. When the enemy did initiate attack, it quickly faded back into the bush when faced with superior U.S. force and overwhelming airpower.
That dynamic changed overnight Jan. 30, 1968, as the divided country prepared to celebrate what many expected to be a quiet Tet, the Vietnamese name for its lunar New Year's Day.
Within days of what would be called the Tet Offensive, 80,000 Viet Cong -- South Vietnamese allied with the Communist north -- and North Vietnamese soldiers had attacked more than 100 towns and cities across South Vietnam. The surprise assaults included parts of Saigon, the southern capital, as well as U.S. and South Vietnamese military bases, supply depots and airstrips.
Shaking off the surprise of such a coordinated and widespread offensive, U.S. military commanders quickly orchestrated counteroffensives with about a half-million American troops deployed there.
Within weeks, most of the Communist fighters had been decimated or driven into the countryside, although a bloody fight would continue for a month in the dynastic city of Hue.
"For the Americans, this was a positive development, that the enemy wasn't running away this time," said Gregory Daddis, an associate professor of history at Chapman University in Orange, Calif., who specializes in the Vietnam War. Military leaders saw the rout as a turning point in the conflict, with the chance to strike a fatal blow to a weakened enemy to achieve victory.
"Some of them were even gleeful, saying that this was just what we wanted," said Christian Appy, a professor of history at the University of Massachusetts-Amherst and author of three books on the Vietnam War.
"The enemy had come out into the open where we could see them and where we could bring our enormous firepower to bear on them," he said.
The Tet Offensive was a turning point in the Vietnam War, but one that irreparably poisoned American public opinion on U.S. involvement and ushered in the steady drawdown of American combat troops. Five years later, American troops had completely withdrawn, and in 1975 North Vietnamese forces stormed into Saigon and reunited north and south.
"I think it was the watershed event of the war; everything that followed changed from what was before Tet," said James Willbanks, author of "The Tet Offensive: A Concise History" and General of the Army George C. Marshall Chair of Military History at U.S. Army Command and General Staff College in Leavenworth, Kan.
"It was the turning point by which the majority of American people finally concluded the war was either not worth the cost or was a mistake," Appy said. "And a growing number had concluded that it was immoral."
The Tet Offensive arrived on the heels of a 1967 publicity blitz by President Lyndon Johnson's administration to convince an increasingly skeptical U.S. public that the Vietnam War was not the stalemate that it appeared to be. Defense and military officials painted a picture of a weakened enemy nearing collapse.
Gen. William Westmoreland, commander of U.S. forces in South Vietnam, said during a speech at the National Press Club in November 1967 that U.S. forces had reached a point where "the end begins to come into view" and that "the enemy's hopes are bankrupt."
"Through 1967, it's hard to exaggerate how much effort the White House put into -- and it even called it this -- the 'success campaign,' propaganda campaign, to convince the American people that the war was going in the right direction, even when internally they weren't at all sure," Appy said.
The campaign was perhaps too convincing, given what the North Vietnamese unleashed in January 1968, a fulsome attack that underscored how far the North was from defeat. The U.S. military deemed the heavy enemy casualties as an American victory, but the U.S. public focused on a determined enemy that inflicted unacceptable loses on fellow countrymen.
"For an American public that is increasingly persuaded by that argument, when the Tet Offensive happens, there seems to be a disconnect between what they've been told and what they're seeing on the ground," Daddis said. Communist fighters chose six strategic targets in downtown Saigon, among them the U.S. Embassy, the presidential palace and the national radio station.
Media images were plentiful and stark.
"The offices and homes of the Western press corps were clustered mainly in downtown Saigon, within walking distance of the palace and U.S Embassy," said Peter Arnett, a correspondent covering the war for The Associated Press. While the number of insurgents were too few to hold their targets for very long, the media images gave Americans a glimpse of an atrocious new breed of violence.
In Saigon on Feb. 1, Brig. Gen. Nguyen Ngọc Loan, chief of the national police, publicly executed a man believed to be the head of a Viet Cong assassination squad. AP photographer Eddie Adams and an NBC television crew captured on film the moment Nguyen shot the handcuffed man through the head.
American counterattacks in the Chinese district of Cholon in Saigon are believed to have killed hundreds of civilians. Scenes of terrified refugees pouring from the district were beamed around the world.
Westmoreland decried the media coverage as too obsessed with "gloom and doom," Arnett said.
"Speaking for my colleagues working in Saigon at that time, our intention was to report and photograph the reality of what we were seeing before our eyes every day," he said. "Our coverage was as professional as we could achieve under difficult circumstances. That our coverage was said to polarize the American public's view of the war was not our intent."
Far to the north, just 30 miles below the demilitarized zone dividing north and south, the city of Hue was overrun by almost 8,000 North Vietnamese troops. The U.S.-South Vietnamese counteroffensive to retake the city was the longest, bloodiest battle of the Vietnam War.
The enemy had dug into a massive complex called the Citadel, which was surrounded by a moat and stone ramparts, some as thick as 40 feet.
More than 200 American troops died in the 25-day battle, with 1,584 wounded; 452 South Vietnamese soldiers were killed.
After hearing reports of unprecedented destruction in South Vietnamese villages, Arnett joined a press trip Feb. 7 to the small provincial capital city of Ben Tre, which he'd visited only weeks earlier. There he saw the ruins of shacks, homes, businesses and restaurants badly damaged by U.S. artillery and airstrikes during the attempt to dislodge Viet Cong who had occupied it during the Tet Offensive. Hundreds of civilians had been killed.
Arnett interviewed a dozen military advisers in the town, who explained how the U.S. and South Vietnamese military compounds had been nearly overrun when they finally requested the heavy shelling.
An utterance by one of those advisers made it into the lead of Arnett's next AP dispatch, which in the 50 years since it was written has been often cited as the essence of America's quixotic involvement in Vietnam: "It became necessary to destroy the town in order to save it." subhead: Strategic success
The North Vietnamese were demoralized in the wake of their failure.
"They'd convinced themselves that they had enough support in the countryside that if they raised the level of violence there, the people would rise up and join them," Willbanks said. That didn't happen. The Viet Cong suffered particularly heavy losses.
Willbanks, who was deployed to South Vietnam in 1972, never saw any Viet Cong during his tour. "They had been wiped out in '68 and hadn't been rebuilt," he said.
But the Tet Offensive did set into motion developments in the U.S. that ultimately turned a failed assault into a strategic success.
Tet had deepened an ongoing internal debate within the Johnson administration between those who wanted to intensify the war -- mainly military leaders -- and those who wanted to de-escalate, primarily civilian advisers, said Mark Moyar, author of "Triumph Forsaken: The Vietnam War, 1954-1965" and director of the Military and Diplomatic History Project at the
Center for Strategic and International Studies.
Some military leaders saw a window of opportunity in the days after Tet began when there was a "rally-around-the-flag effect" among Americans, similar to what happened after the Pearl Harbor attack in 1941, he said.
"Once Johnson made it clear that he was not going to take more aggressive measures, then you saw public support tail off," he said.
Johnson lost what little stomach he'd had for the war after Tet, and it played a role in his decision to not seek a second term that fall, clearing the way for Richard Nixon's election.
"When Nixon came to office he realized that the American public would no longer support high levels of American troops or casualties and so announced that he would slowly withdraw troops, even, of course, as he expanded the war into Cambodia and Laos and intensified the air war," Appy said.
Meeting with South Vietnamese President Nguyen Van Thieu at Midway Island in June 1968, Nixon announced that 25,000 U.S. troops would be withdrawn by the end of August and that South Vietnamese troops would eventually assume all combat responsibilities.
Before Tet, "we were there to win the war," Willbanks said. Everything after that was geared to "build the South Vietnamese forces up, turn the war over to them and depart."
"I think that weighs heavily on individual soldiers who are still being asked to fight out in the field," Daddis said. "They begin to question the rationale behind what they're being asked to do at that unit level. Why am I risking my life if we're not even going to win?"
Appy, however, is unconvinced by claims that "victory was in sight after Tet and we just didn't finish the job."
"There was never going to be a military solution to the war," he said. "My point is victory was never going to happen in South Vietnam unless and until the government in Saigon had the support of its own people necessary to sustain it without massive American military intervention," Appy said.
Daddis said Tet remains a compelling story in large part because for some it remains this one central moment in the entire Vietnam War where they ask, 'What if?'
"This is really one of the central counterfactuals that some will focus on because this seems to be the moment where the American effort really starts to unravel.
"It remains this key storyline because it seemed like victory was within our grasp, at least from a military standpoint, but was politically taken away by politicians, the media and the public that just didn't see the true victory that was there. That's a very problematic argument, but I think that's why it remains such a centerpiece of debate over what happened in Vietnam."
But war, Daddis contends, is not simply about military victories and losses.
"I'm not all that personally convinced of arguments that suggest there was a military victory but a political defeat [with Tet] because that unnaturally separates what war is," he said. "War is a much more political act than it is a military one."