U.S. President Donald Trump, in a letter to Turkish President Tayyip Erdogan before Turkey launched an operation into Syria, warned the Turkish leader "don't be a tough guy" and "don't be a fool!"
The Oct. 9 letter was released by the White House as Trump battled to control the political damage following his decision to pull U.S. troops out of northern Syria, clearing the way for the Turkish operation against America's YPG allies.