I'm going to triple post this because it relates to the Iraq, Syria & Turkey threads. Pardon the repetition.

Just wrote an article on Turkey's decision to join the US led coalition against IS. Three main points to take away:

1) Turkey is going to follow its own policy which conflicts with the U.S. Obama admini thinks it can change Erdogan's view in the long term while getting right to use Turkish bases in the short. Obama only has little more than a year in office however so Turkey will probably win out in the long run.

2) Turkey wants to punish the PKK/PYD into submission and make it a client like it's done to the KRG

3) Finally Turkey wants to give more direct aid to the Syrian rebel groups its supports like Al-Nusra with the Syrian Free Zone.

Here's the full article