1972 in the Vietnam War the number of air raids against North Vietnam during all of 1971. Prime Minister Lon Nol declared President of Cambodia. Unlike the former Cambodian leader, Norodom Sihanouk, Lon Nol was a U.S. ally. The U.S. 101st Airborne Division left South Vietnam, the last U.S. ground combat division to be withdrawn from South Vietnam. The Khmer Rouge bombarded with artillery Phnom Penh, the capital city of Cambodia, killing more than 100 civilians. This was the heaviest attack on Phnom Penh since the Cambodian Civil War began in 1970. The United States boycotted peace negotiations in Paris with the North Vietnamese, citing
1972 in the Vietnam War The United States Joint Chiefs of Staff assessed the performance of South Vietnamese armed forces thus far in the Easter offensive as "encouraging." The city of Quang Tri was captured by the communist forces, the only provincial capital to fall to them during the Easter Offensive. The preceding week saw South Vietnamese casualties, especially near Quang Tri, reach their highest level of the entire Vietnam War. Two combat divisions of South Vietnam collapsed and fled the fighting. President Nixon withdrew his demand for a withdrawal of all North Vietnamese forces from South Vietnam as a precondition for a peace agreement.