Under the Obama administration, Turkey began making overtures to the Kremlin, as it realized it needed closer relations with Moscow. Mr. Putin, recognizing the valuable strategic importance of Turkey, as well as being a NATO country, was quick to step up with Turkey. Mr. Putin didn't miss a stroke to capitalize on Mr. Obama's great weaknesses in foreign affairs 
For 8 years, the Obama administration allowed the relationship to deteriorate with Turkey due to his inept ability to handle the Syrian situation, and having backed down from the red line he drew. Mr. Obama was not only a weak leader, but his weakness put Russia in the catbird seat in Syria, leaving Turkey to realizing if anything was to get done it would have to go through the Kremlin versus Washington
Sad that much of what Mr. Trump must deal with today is the leftovers of past administrations in Washington, who either appeased or were just plain weak as Mr. Obama was. I call it the "kick the can down the road" let it fester.