In coordinated attacks all across South Vietnam, communist forces launch their largest offensive of the Vietnam War against South Vietnamese and U.S. troops.

Dozens of cities, towns, and military bases—including the U.S. embassy in Saigon—were attacked. The massive offensive was not a military success for the communists, but its size and intensity shook the confidence of many Americans who were led to believe, by the administration of President Lyndon B. Johnson, that the war would shortly be coming to a successful close.

On January 30, 1968-during the Tet holiday cease-fire in South Vietnam-an estimated 80,000 troops of the North Vietnamese Army and National Liberation Front attacked cities and military establishments throughout South Vietnam. The most spectacular episode occurred when a group of NLF commandos blasted through the wall surrounding the American embassy in Saigon and unsuccessfully attempted to seize the embassy building. Most of the attacks were turned back, with the communist forces suffering heavy losses.

Battles continued to rage throughout the country for weeks–the fight to reclaim the city of Hue from communist troops was particularly destructive. American and South Vietnamese forces lost over 3,000 men during the offensive. Estimates for communist losses ran as high as 40,000.

While the communists did not succeed militarily, the impact of the Tet Offensive on public opinion in the United States was significant. The American people, who had been told a few months earlier that the war was successful and that U.S. troops might soon be allowed withdraw, were stunned to see fighting taking place on the grounds of the U.S. embassy.

Despite assurances from the Johnson administration that all was well, the Tet Offensive led many Americans to begin seriously questioning such statements, and to wonder whether American military might could truly prevail over the communist threat on foreign shores. In the 1950s, Americans had almost unconditionally supported a vigorous American response to communism; the reaction to the Tet Offensive seemed to reflect the growing skepticism of the 1960s, when Americans felt increasingly doubtful about the efficacy of such Cold War tactics. In the wake of the Tet Offensive, support for the U.S. effort in Vietnam began steadily to decline, and public opinion turned sharply against President Johnson, who decided not to run for re-election.