I agree with scat. It's the flash point for the sunni/shia battle, but why does that concern us? Because Obama has made a mess of it, with ridiculous threats of red lines, etc that he promptly ignored? Because Putin has come to the aid of his ally, to devastating effect? Because it is so important to our national interest to drive out the current dictator, an iran ally, and replace him with ISIS thugs?
The only threat to any vital interest of the US is the reckless actions of a supposed NATO ally, Turkey. Turkey once was the model secular muslim state but now is under the grip of the sort of repressive islamist thugs that obama tried to get into power in Egypt. Turkey is openly aiding our enemy ISIS and bombing our allies, the kurds. Yet we are under a treaty obligation to support them if they manage to blunder into a shooting war with Russia. Great, just great.
The main thing this episode demonstrates is how NATO is now outdated and serves to endanger us. Europe is completely capable of protecting themselves. They would just prefer that we spend ourselves into oblivion doing it for them, while they export expensive cars to us.