In contrast to the air attacks on North Vietnam, the U.S.-South Vietnamese war effort in the south was fought on the ground, largely under the command of General Westmoreland, in coordination with the government of General Nguyen Van Thieu in Saigon. In general, U.S. military forces in the region pursued a policy of attrition, aiming to kill as many enemy troops as possible rather than trying to secure territory. By 1966, large areas of South Vietnam had been designated as “free-fire zones,” from which all innocent civilians were supposed to have evacuated and only enemy remained. Heavy bombing by B-52 aircraft or shelling made these zones uninhabitable, as refugees poured into camps in designated safe areas near Saigon and other cities. Even as the body count (at times exaggerated by U.S. and South Vietnamese authorities) mounted steadily, DRV and Viet Cong troops refused to stop fighting, encouraged by the fact that they could easily reoccupy lost territory. Meanwhile, supported by aid from China and the Soviet Union, North Vietnam strengthened its air defenses.

By November 1967, the number of American troops in Vietnam was approaching 500,000, and U.S. casualties had reached 15,058 killed and 109,527 wounded. As the war stretched on, some soldiers came to mistrust their government’s reasons for keeping them there, as well as Washington’s claims that the war was being won. The later years of the war saw increased physical and psychological deterioration among American soldiers, including drug use, mutinies and attacks by soldiers against officers and noncommissioned officers.

Bombarded by horrific images of the war on their televisions, Americans on the home front turned against the war as well: In October 1967, some 35,000 demonstrators staged a mass antiwar protest outside the Pentagon. Opponents of the war argued that civilians, not enemy combatants, were the primary victims and that the United States was supporting a corrupt dictatorship in Saigon.