President Trump had been calling Turkish President Recep Tayyip Erdoğan’s bluff for more than 2 years, and some senior administration officials thought Erdoğan would never actually go through with his long-threatened Syria invasion, according to 6 sources with direct knowledge of the situation.

“I think everyone thought Erdoğan was bluffing.”
— A source close to Trump

The big picture: Trump would tell Erdoğan that if he wanted to invade Syria he would have to own whatever mess ensued, according to these sources. Erdoğan would have to take care of ISIS and manage international condemnation, trouble from Capitol Hill, and the quagmire with the Kurds. And when Trump put it in such stark terms to Erdoğan, the Turkish leader would demur. Until last Sunday, that is, when he told Trump he was moving ahead with the invasion of northern Syria.