Plausibility Check: Sino-Soviet Split leads to all-out War?

In the 60's the once "allies" began to split over differing interpretations over relations with/attitudes towards Capitalist countries, not to mention Mao's various programs/revolutions. Words soon turned to armed conflict by the late 60's. Though things soon cooled down (to an extent) could this have gone further??

And if so, would America join either side or just let them tear each other apart??

Just curious to see if this was plausible. And if so, how?
 
I think that it's plausible, but will be devastating for China, even if they win, and could spell the end of the Warsaw Pact whether the USSR wins or loses. The trouble is getting the right spark to start the war.

THe Americans will sit this one out, but expect the conflict to impact the prosecution of the Vietnam conflict.
 
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