History of Vietnam since 1945 unstable as no government could keep power for long. There were more coups, often more than one every year. The Communist-run Viet Cong expanded their operation and scored some significant military victories during this period. In 1965, US President Lyndon Johnson sent troops to South Vietnam to secure the country and started to bomb North Vietnam, assuming that if South Vietnam fell to the Communists, other countries in the Southeast Asia would follow, in accordance with the domino theory. Other US allies, such as Australia, New Zealand, South Korea, Thailand, the Philippines, and Taiwan also sent troops to South Vietnam.
China in the Vietnam War the revolution deeper into Southeast Asia via the Indochinese internationalist model. Then relations changes in the late 1960s, as the Cultural Revolution and Maoist visions of permanent revolutionary struggle ran up against important and extremely complex geostrategic differences in Vietnam in the war against the US. Nonetheless, the Chinese continued to supply massive amounts of military and economic aid, as well as sending over 300,000 military support troops into northern Vietnam. Internationalism did suffer a serious blow, plus the Sino-Soviet split, which brought damage to the relations between China, the Soviet Union and of course, Vietnam. Vietnam War: https://en.wikipedia.org/wiki/Vietnam_War First