Tet Offensive

The Tet Offensive was both a major escalation and one of the largest military campaigns of the Vietnam War. The North Vietnamese People's Army of Vietnam (PAVN) and the Viet Cong (VC) launched a surprise attack on 30 and 31 January 1968 against the forces of the South Vietnamese Army of the Republic of Vietnam (ARVN), the United States Armed Forces and their allies, targeting military and civilian command and control centers throughout South Vietnam. The name is the truncated version of the Lunar New Year festival name in Vietnamese, Tết Nguyên Đán, a holiday period when most ARVN personnel were on leave. The North Vietnamese Politburo and leader Lê Duẩn intended to trigger political instability and that mass armed assaults on urban centers would trigger defections and uprisings.

The offensive was launched prematurely in the early morning hours of 30 January in large parts of the I and II Corps Tactical Zones of South Vietnam. This allowed allied forces some time to prepare defensive measures. When the main operation began during the early morning of 31 January, the offensive was countrywide; 77,000 PAVN/VC troops struck more than 100 towns and cities, including 36 of 44 provincial capitals, 5 of 6 autonomous cities, 72 of 245 district towns, and the capital Saigon. It was the largest military operation conducted by either side by that point in the war.

Hanoi launched the offensive in the belief it would trigger a popular uprising leading to the collapse of the South Vietnamese government. Although the initial attacks stunned the allies and they lost control of several cities temporarily, they quickly regrouped, repelled the attacks, and inflicted heavy casualties on PAVN/VC forces. The popular uprising anticipated by Hanoi never materialized. During the Battle of Huế, intense fighting lasted for a month, resulting in the destruction of the city. During its occupation, PAVN/VC forces executed thousands of people in the Massacre at Huế. Around the American combat base at Khe Sanh, fighting continued for two more months.

The offensive was a military defeat for North Vietnam, and neither uprisings nor ARVN unit defections occurred in South Vietnam. However, it had far-reaching consequences on the views of the Vietnam War held by the American public and the international community. The offensive had a strong effect on the U.S. government and shocked the American public, which had been led to believe by its political and military leaders that the North Vietnamese were being defeated and incapable of launching such an ambitious military operation. American public support for the war declined as a result of the Tet casualties and the escalation of draft calls. Subsequently, the Johnson administration sought negotiations to end the war. Shortly before the 1968 United States presidential election, Republican candidate and former vice president Richard Nixon encouraged South Vietnamese president Nguyễn Văn Thiệu to become publicly uncooperative in the negotiations, casting doubt on Johnson's ability to bring peace.

The name "Tet Offensive" usually refers to the January–February 1968 offensive, but also can be extended to cover all of the 21 weeks of intense combat after the initial attacks in January (including the "Mini-Tet" offensive in May), or the Phase III offensive in August.