Considering a big part of Putin's annexation of the Crimea was for Black Sea ports...
(though Wilbur's insinuation that the war in Syria is really just Erdogan's machinations is a tad silly)
Really? So tell me why Erdogan has been bombing the Kurds who are fighting ISIS while they're on the Syrian and Iraqi side of the border? And why these are the same Kurd fighters who have been effective against ISIS; plus, they US is about to send 50 special forces soldiers to train and 'assist' them?
You are oversimplifying. Different countries, although wanting Assad to be ousted, have different interests. Qatar wants to build a pipeline through Syria through Turkey for exporting its gas; Assad didn't want to cooperate, so Qatar is funding and arming Al-Qaida in Syria. Saudi doesn't like the secular state of Syria led by Assad the apostate/Shiite/Alawite, and the fact that they're allied with arch enemy Iran; Saudi Arabia wants to spread its medieval Islamic fundamentalist Salafism there without Shiite 'dirt' having any influence; so they have been arming and financing ISIS Taqfiris (those who call Shiites apostates and call for their elimination, preferably by beheading). Plus, Assad is allied to Shiite Iran and Hezbollah, along with now Shiite Iraq (thanks to the Americans, believe it or not).
Turkey's interests will clash with Saudi Arabia, since both want to run the Levant. In fact, the US policy in the ME is no longer coherent.
Turkey goals and US goals are diverging. US is keeping mum on Turkey because they don't want to jeopardize the leases they have on their air bases in Turkey.
As for Crimea, annexation was a product of the US instigated coup that took place in Kiev, and the possibility that Kiev would break the 40 year lease agreement with Russia of the naval base at Sevastopol, home of the Russian Black Sea fleet, and the resulting possibility that the present regime in Kiev would hand it over to the US/NATO. Russia could not take the chance of this happening. Plus, the 90% ethnic Russian inhabitants of Crimea didn't want to be part of what was to become the economic and political basket case that is now the Ukraine.