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Come on in, the quicksand is fine.
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Actually, Russia is a much better fit here that the US is. Russia allies, Iran and Syria (along with Iraq) are either Shite states (Iran) or Shite dictators ruling over Sunnis (Syria and - one could argue - Iraq). Them bombing the hell out of Sunni resistance makes marginal geo-political sense.
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On the other hand US allies (Saudi Arabia, the Gulf States, Egypt, Turkey) are mainly Sunni's in some cases ruling over large Shite populations (Bahrain). So for the US, the fight against ISIS will always be tough. Not they they are not bad guys - heck really bad guys. But because they are the most effective fighting force against the Shite forces. The US tried to solve this by training non-ISIS Sunni freedom fighters. After bringing over something like 1000 to train, there are 9 left in the field fighting that didn't run away, join ISIS or join Al Queda (those were in descending order of popularity).
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So Russia gets to join the quagmire. And they politely told the US airplanes to clear the airspace as they bombed ISIS.
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It's nice to note they don't learn either. They got screwed in Afghanistan and got out of the middle east - and now they are back! We got screwed in Afghanistan and Iraq and now we are back.