The United States fought wars in Korea and Vietnam to contain communism. In Korea, it went full scale right away, and invaded the North. Americans and Chinese actually fought and killed each other directly, no proxies necessary. In Vietnam, escalation was slow and steady, and it never invaded the North. What would have had to change for the US to go all out right away, or reach that point eventually, in Vietnam? How much more bloody would the conflict have gotten? Would China get involved directly? Would the result change? What would have been the repercussions?