Exploiting a traditional truce for the Tet lunar new year holiday, North Vietnamese and Viet Cong forces struck simultaneously across South Vietnam, hitting provincial capitals, military bases, and Saigon itself. A Viet Cong squad even breached the U.S. Embassy compound. Though American and South Vietnamese forces eventually repelled the attacks with heavy communist losses, the offensive shattered official claims that the war was nearly won and turned American public opinion decisively against the conflict.
For years, U.S. commanders including General William Westmoreland had assured Washington and the American public that victory was in sight, that the enemy was being ground down by attrition. Tet detonated that narrative in a single night. Roughly 80,000 communist troops attacked more than 100 towns and cities simultaneously, an operational feat of coordination that stunned American intelligence, which had expected only a lull for the holiday.
In Saigon, a 19-man Viet Cong sapper squad blew a hole in the wall of the U.S. Embassy compound and held the grounds for nearly six hours before being killed or captured, while television cameras and photographers captured the chaos live for American audiences. The ancient imperial city of Hue saw some of the war's bloodiest urban combat, with U.S. Marines fighting street to street for weeks to retake it, only to uncover mass graves of thousands of civilians executed by retreating communist forces.
Militarily, Tet was a communist disaster; the Viet Cong's infrastructure in the south was devastated and never fully recovered. But the psychological impact ran the opposite direction. Walter Cronkite's grim on-air assessment that the war was now unwinnable, and President Johnson's own private despair, marked Tet as the turning point after which American public support for the war collapsed.