Vietnam ground combat operations in 1965, and at their peak they numbered more than 500,000. The US also engaged in a sustained aerial bombing campaign. Meanwhile, China and the Soviet Union provided North Vietnam with significant material aid and 15,000 combat advisers. Communist forces supplying the Việt Cộng carried supplies along the Hồ Chí Minh trail, which passed through the Kingdom of Laos. The communists attacked South Vietnamese targets during the 1968 Tết Offensive. Although the campaign failed militarily, it shocked the American establishment, and turned US public opinion against the war. During the offensive, communist troops massacred over 3,000 civilians
1961 in the Vietnam War of the U.S. Army to respond to Kennedy's emphasis on developing a greater capability in counterinsurgency, although the U.S. Military Assistance Advisory Group began providing counterinsurgency training to the South Vietnamese army (ARVN) and other security forces. The Kennedy Administration debated internally about introducing U.S. combat troops into South Vietnam, but Kennedy decided against ground soldiers. The CIA began assisting Montagnard irregular forces, American pilots began flying combat missions to support South Vietnamese ground forces, and Kennedy authorized the use of herbicides (Agent Orange) to kill vegetation near roads threatened by the Viet Cong. By the end of the year,