Iraqi integracy is not worth the paper the Europeons wrote it on.
Iraq is a artificial post war construct of the europeons, we need to leave it to the people who actually live there to decide where the borders will fall. If it spilts up along ethnic lines the short term pain will be worth the long term stability.
And no, as long as Turkey makes no long term incursions into Kurdistan, the US isn't going to attack a NATO country in order to do the fighting for an islamic terror group, under the pretence of Iraq integrity or no.
The problem is that those borders were drawn more than 80 years ago and now have a long history. Remember when the same thing was said about Yugoslavia, that we should just let it break up into its constituent parts. That was what the Germans said when they recognized Slovania and Croatia. Then all hell broke loose and things are still not settled. You see, the Germans were not prepared to do what was necessary.