Turkish troops and tanks have lined the border but have not crossed into Syria.
I have a hard time thinking that Turkey is against the ideal of a Caliphate. More likely to me, Turkey is against the idea that the Caliphate shaping up will not be a part of the once great Ottoman Empire.
The USA is not now fighting a war against a Caliphate in the Middle East. The USA is fighting a war against the opposition to its homeland.
A Caliphate in the Middle East is not against the interest of the USA, if we convert to natural gas and defend the homeland (the F35 and missile defense). There is a huge anti-war movement shaping-up in the USA that is threatening to move the US’s line of defense towards the Pacific (Obama’s Pivot) and South America, and away for the MENA.
I think my saying that the fight in the Middle East is now against ISIS, but not one against a Caliphate, is also true of the Kingdom of Saudi Arabia (KSA). I am sure both Turkey and KSA are more than willing to battle ISIS, if it means that the Caliphate forming will be more to their image, than that of the Levant.
Perhaps getting into the fight will mean more to Turkey when the Kurds get their own nation-state, which, because of the oil the Kurds hold and the Kurdish population in Turkey, will not be in Turkey’s interest.
In the mean time, Turkey will take advantage of the situation, as that advantage becomes available.
Look out Kurds, get your shit together, because the big-boys are a-coming. If you can’t stand the heat, get out of the fire!