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
Vietnam War South Korea (a.k.a. the Republic of Korea, ROK) had the second-largest contingent of foreign troops in South Vietnam after the United States. In November 1961, President Park Chung-hee proposed South Korean participation in the war to John F. Kennedy, but Kennedy disagreed as they were not SEATO treaty members. On 1 May 1964, Lyndon Johnson agreed to permit South Korean participation under the Many-Flags Program in return for monetary compensation. The first South Korean troops began arriving in 1964 and large combat formations began arriving a year later. The ROK Marine Corps dispatched their 2nd Marine Brigade, while the ROK