Donald Trump and Recep Tayyip Erdogan November 7, 2018.Christophe Licoppe | Photonews | Getty ImagesPresident Donald Trump sent a letter to Turkish President Recep Tayyip Erdogan last week warning him not to “let the world down” through his military incursion in northern Syria against the Kurds.”Let’s work out a good deal!” Trump said in the Oct. 9 letter, which was first reported by Fox Business Network and later confirmed to CNBC by White House officials.The letter continues:”You don’t want to be responsible for slaughtering thousands of people, and I don’t want to be responsible for destroying the Turkish economy—and I will. I’ve already given you a little sample with respect to Pastor Brunson.I have worked hard to solve some of your problems. Don’t let the world down. You can make a great deal. General Mazloum is willing to negotiate with you, and he is willing to make concessions that they would never have made in the past. I am confidentially enclosing a copy of his letter to me, just received.History will look upon you favorably if you get this done the right and humane way. It will look upon you forever as the devil if good things don’t happen. Don’t be a tough guy. Don’t be a fool!I will call you later.”The letter, using language and punctuation reminiscent of Trump’s often incendiary Twitter account, was written on the same day that Turkey launched military operations against the Kurds near Syria’s northern border.The incursion came less than a week after the White House revealed that the U.S. would withdraw forces in that area.The abrupt foreign policy shift was condemned by members of both major parties as a “green light” for Turkey to attack the Kurds, who were integral to U.S. operations against ISIS.Trump has denied that he gave Turkey permission to attack the Kurds, some of whom have called the U.S. pullback a “betrayal.”A White House delegation that includes Vice President Mike Pence and Secretary of State Mike Pompeo is set to depart for Turkey on Wednesday evening for a meeting with Erdogan, who had initially rebuffed their outreach.