AH Challenge: Largest Conventional War Post-Nukes

Especially in regards to the Cold War scenarios, it seems that a lot of threads involving war between, say, NATO and the Warsaw Pact end in nuclear warfare. Understandably, that would suck for everyone involved.

With a POD post-1945, what is the largest conceivable conventional war possible? For the sake of clarification, by "conventional" I mean no nukes, but other so-called weapons of mass destruction are allowed, as long as they're within reason.

I'm specifically looking for a war that doesn't involve the USSR versus the States, or any other Cold War-esque scenario. Be creative, and for the most part try to construct it to be as plausibly big as possible.
 
Tough question... Maybe a full scale war between India and China before either developed nuclear weapons? The hostile terrain of their border region makes it hard for anything even approaching WW2 levels, though, as seen in OTL. The United Arab Republic vs. the Baghdad Pact (the UK, Turkey, Iraq, Iran and Pakistan) in the 1960s? Somehow, the UAR stays together, and Iraq doesn't have a republican coup. Lebanon and Israel could get involved, too, and maybe Saudi Arabia, just to add more fuel to the fire.
 
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