Chapter 6 assesses the impact of US air power as the ARVN shifted its offensive into southern Laos in 1971. After the Cambodian incursion, a Democratic Party-led Congress voted the Cooper–Church amendment into law, forbidding US ground troops beyond South Vietnamese borders. The ARVN objective in Laos was to achieve what US air power alone during Commando Hunt was unable to do: close off the Ho Chi Minh Trail. Instead, the ill-fated Lam Son 719 raid revealed significant shortcomings in allied air–ground coordination. The South Vietnamese, minus their US military advisors and tactical air controllers, could not take advantage of the available air power to prevent the NVA from driving the ARVN from Laos. After the NVA’s victory, the North Vietnamese gambled with another general offensive.

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.