Lyndon Johnson's decision to Americanise the war in Vietnam in 1965 had been a deeply thought-out one, though not free of risk nor immune to contingencies. As will be seen, a particular presidential concern after the US combat intervention had begun was to enlist as many allies as possible to help legitimise the war. However, the results of the recruitment campaign fell short of what was desired; no NATO state, for example, provided combat assistance. The US military performed well in larger-scale engagements, although there was inadequate attention to ‘pacification’, that is, securing populated areas from communist influence. Rolling Thunder, the air campaign that had begun early in 1965 and continued to the end of 1968, played a modest role in minimising the infiltration of troops and material into the South, but large areas of North Vietnam remained untouched out of fear of Chinese intervention. The chapter then examines some of the third-party efforts to promote peace. Neither the United States nor the North Vietnamese were willing to make a significant compromise of their respective positions, and the involvement, though usually well-intentioned, of third parties was likely only to complicate matters without advancing the cause of peace. As such, the war went on. The United States and the South Vietnamese were able to defeat the communists' Tet Offensive in 1968 but the very fact that a large-scale assault could be launched in the first place shocked many observers and prompted a reappraisal of the war in Washington.