I thought it was a typo or something but I read that the United States provided support to the Khmer Rouge because it would weaken Vietnam's influence or something like that. From how evil the Khmer Rouge was (plus being communist) I'm just not seeing the reasoning here behind U.S. involvement. What am I missing?
Not to discourage any more discussion here but I’ve answered some similar questions lately that might interest you
Short answer ? Yes. Not during 1975-9, but after - and mostly financially - to destabilise the Vietnamese who had set up a government in Cambodia after the third Indochinese war, also because of rapprochement with China.