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.