The Tet Offensive
On January 21, 1968, an intense barrage of artillery hit the US Marine base at Khe Sanh in northwest South Vietnam. This presaged a siege and battle that would last for seventy-seven days and would see 6,000 Marines hold off 20,000 North Vietnamese. Anticipating that American forces would be drawn north to the fighting at Khe Sanh, Viet Cong units broke the traditional Tet (Lunar New Year) cease-fire on January 30, 1968, by launching major attacks against most cities in South Vietnam.
For the next two months, US and ARVN forces successfully beat back the Viet Cong assault, with particularly heavy combat in the cities of Hue and Saigon. Once the fighting had ended, the Viet Cong had been permanently crippled and ceased to be an effective fighting force. On April 1, US forces began Operation Pegasus to relieve the Marines at Khe Sanh. After opening the road to Khe Sanh (Route 9) with a mix of air mobile and ground forces, US troops linked up with the besieged Marines on April 8.
While the Tet Offensive proved to be a military victory for the US and ARVN, it was a political and media disaster. Public support began to erode as Americans started to question the handling of the conflict. Others doubted Westmoreland’s ability to command, leading to his replacement in June 1968, by General Creighton Abrams. President Johnson’s popularity plummeted and he withdrew as a candidate for reelection. Ultimately, it was the media’s reaction and stressing of a widening “credibility gap” that did the most damage to the Johnson Administration’s efforts. Noted reporters, such as Walter Cronkite, began to openly criticize Johnson and the military leadership, as well as called for negotiated end to the war. Though he had low expectations, Johnson conceded and opened peace talks with North Vietnam in May 1968.
Nixon & Vietnamization
Campaigning under the slogan “Peace with Honor,” Richard M. Nixon won the 1968 presidential election. His plan called for the “Vietnamization” of the war which was defined as the systematic build up of ARVN forces to the point that they could prosecute the war without American support. As part of this plan, American troops would slowly be removed. Nixon complemented this approach with efforts to ease global tensions by reaching out diplomatically to the Soviet Union and People's Republic of China. In Vietnam, the war shifted to smaller operations geared towards attacking North Vietnamese logistics.
While the antiwar movement in the US was pleased with Nixon’s efforts at détente with communist nations, it was inflamed in 1969, when news broke about a massacre of 347 South Vietnamese civilians by US soldiers at My Lai (March 18, 1968). Tension grew further when, following a change in stance by Cambodia, the US began bombing North Vietnamese bases over the border. This was followed in 1970, with ground forces attacking into Cambodia, a move viewed as expanding the war rather than winding it down. Public opinion sunk lower in 1971 with the release of the Pentagon Papers. A top secret report, the Pentagon Papers detailed American mistakes in Vietnam since 1945, as well as exposed lies about the Gulf of Tonkin Incident, detailed US involvement in deposing Diem, and revealed secret American bombing of Laos. The papers also painted a bleak outlook for American prospects of victory.
Despite the incursion into Cambodia, Nixon had begun the systematic withdrawal of US forces, lowering troop strength to 156,800 in 1971. That same year, the ARVN commenced Operation Lam Son 719 with the goal of severing the Ho Chi Minh Trail in Laos. In what was seen as a dramatic failure for “Vietnamization,” ARVN forces were routed and driven back across the border. Further cracks were revealed in 1972, when the North Vietnamese launched a conventional invasion of the south, attacking into the northern provinces and from Cambodia. This offensive was only defeated with the support of US airpower (Operation Linebacker).