The Turks have now let 100,000 plus Syrian Kurds into their country as they flee the IS headchoppers. Good for them!At the same time Turkish police have shown up at the border north of the city of Kobane which is under IS attack for the purpose of preventing Turkish Kurds from crossimg the border to fight alongside their ethnic kinsmen. Many of those who want to cross are Turkish Army and Jandarma veterans who are well trained.
Erdogan's police are using water cannons and tear gas to prevent their crossing. Why wuould Erdogan do that?
IMO, Erdogan, who has always supported IS has made a deal in which he will continue to deny NATO the use of facilities and will continue to support IS sub rosa (sort of). In this case he is helping IS cut its way to the Turkish border where logistical and other support will be easier to provide. At the same time this allows IS to clear up yet another space in its rear area before moving on to other matters.
In short, Turkey is now both a member of NATO (lapsed) and part of the Sunni salafi coalition headed by IS. Turkey should be required to choose which role it wants for itself and should be held to that choice.