CIA activities in Vietnam the next 14 years, the focus of their paramilitary operations changed over time. Until 1964, the Hmong fighters in Laos focused on trying to fight back North Vietnamese fighters and on preventing further encroachment. They were highly important, because the US hadn't begun putting troops on the ground in any great numbers, yet. After that, in 1965, the report describes the Hmong activities in Laos as "flitt[ing] over mountain trails or mov[ing] by air to occupy key high ground and to harass Hanoi's tanks and artillery," meaning that US troops took on a frontline role and asked the paramilitary forces
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