At the prompting of the Nixon White House, President Nguyen Van Thieu sent South Vietnamese forces into Laos in February 1971, seeking to cut North Vietnamese supply lines to the battlefields in the South. Lam Son 719 was a bloody failure, and it shaped the final phase of America’s Vietnam War. Convinced that the South Vietnamese could never withstand a full-scale offensive, the North Vietnamese leadership committed to a nation-wide attack in early 1972, designed to bring a decisive end to the war. The Easter Offensive, as it is remembered in the West, broke on three fronts in late March 1972, initially with a series of victories by the NVA. President Richard Nixon and his national security advisor, Henry Kissinger, viewed this offensive as a threat to their political and diplomatic objectives, and ordered a massive deployment of US air and naval forces to reinforce the South Vietnamese. In May 1972, Nixon ordered an air offensive against North Vietnam code-named Linebacker to deny resupply to the North Vietnamese forces. The NVA offensive stagnated in late June, setting the stage for negotiations between the US and Hanoi to end the war. Kissinger and Le Duc Tho reached a settlement in early October, but it was rejected by Thieu, forcing the US to renegotiate the treaty. In the end, Nixon directed the most violent air campaign of the war, sending B-52 heavy bombers over Hanoi to coerce the North Vietnamese into accepting the minor changes required for a settlement.

From a strategic standpoint, the final years of the American war in Vietnam highlighted a persistent uncertainty over how the conflict would end. Both civil and military leaders wrestled with confusing estimates on the war’s progress. These uncertainties mattered because they influenced the timing of and ways in which US forces withdrew from a war that would not end once the Americans had departed. Despite arguments that General Creighton Abrams had fought a “better war” in Vietnam leading to a military victory, a sense of strategic stalemate hung over these final years. Problems remained in assessing the political aspects of pacification, the staying power of the South Vietnamese armed forces once American troops departed, and the longterm viability of the Saigon regime. By early 1969, Abrams also had to confront political decisions leading to the first withdrawal of US troops, decisions that would pit him against the Nixon administration and bring to the surface grave civil–military tensions. Despite years of effort, a key question remained unanswered as these withdrawals began – how stable would South Vietnam be once Americans departed? Ultimately, these final years left the Americans no closer to answering the question of whether they would achieve “victory” in Vietnam.

Chapter 5 assesses US air power following the Tet Offensive through the cross-border incursion into Cambodia in 1970. The newly elected US president, Richard Nixon, sought an American withdrawal from South Vietnam. However, he initially expanded the conflict into Cambodia to deny the NVA/VC sanctuary and sever their southern supply lines. Leading up to the invasion, the Commando Hunt air interdiction campaign in southern Laos slowed the movement of supplies. It also imposed substantial costs on the North to keep the Ho Chi Minh Trail open. Commando Hunt could not halt the NVA troops from making the journey to South Vietnam on foot, but the direct attack of fielded forces in South Vietnam and Cambodia did continue to keep the NVA/VC dispersed and hidden. Keeping the North Vietnamese on the defensive provided the time and space for South Vietnam’s pacification program to take root and for the Vietnamization program to generate conventional capabilities for the Army of the Republic of Vietnam (ARVN) to replace withdrawing American combat troops.