Vietnam War remained in the field for four days. Tellingly, South Vietnamese forces were again defeated in June 1965 at the Battle of Đồng Xoài. On 8 March 1965, 3,500 U.S. Marines were unilaterally dispatched to South Vietnam. This marked the beginning of the American ground war. U.S. public opinion overwhelmingly supported the deployment. The Marines' initial assignment was defensive. The first deployment of 3,500 in March 1965 was increased to nearly 200,000 by December. The U.S. military had long been schooled in offensive warfare. Regardless of political policies, U.S. commanders were institutionally and psychologically unsuited to a defensive mission. General William
Joint warfare in South Vietnam, 1963–1969 Vietnam, and the 173rd Airborne Brigade for the Bien Hoa/Vũng Tàu area near Saigon. Early, CINCPAC had objected to the use of the 173rd, since it was the primary strategic reserve for Pacific Command. Westmoreland, in early June, saw the situation as close to collapse without a major commitment of ground troops, in addition to the ARVN. This triggered several weeks of intense debate among the President's close civilian advisers, with McNamara controlling all direct military input to the process. There were two drivers among the inner circle. First, some, but not all, were fervent believers in the containment doctrine,