In a late-night press release, the White House announced that Turkey "will soon be moving forward" with an invasion of northern Syria—areas currently occupied by Kurds.
Mr. Trump's decision goes against the recommendations of top officials in the Pentagon and the State Department who have sought to keep a small troop presence in northeast Syria to continue operations against the Islamic State, or ISIS, and to act as a critical counterweight to Iran and Russia. Administration officials said that Mr. Trump spoke directly with President Recep Tayyip Erdogan of Turkey on the issue on Sunday. And the officials indicated that the 100 to 150 United States military personnel deployed to that area would be pulled back in advance of any Turkish operation but that they would not be completely withdrawn from Syria.
The Kurds were key allies in the war on ISIS, and Trump is fully aware that withdrawing U.S. support for them could mean ethnic cleansing by the Turks, because he's boasted of stopping it in the past by not withdrawing.
On Monday a spokesman for the Kurdish-led Syrian Democratic Forces (SDF) – who occupy former IS territory in north-eastern Syria – strongly condemned the US move.
"There were assurances from the United States of America that it would not allow any Turkish military operations against the region," Kino Gabriel told Arabic TV station al-Hadath.
He added: "The (US) statement was a surprise and we can say that it is a stab in the back for the SDF."
Erdogan told Trump to do it, so he did it. This morning other people will tell him not to do it, so he might try to change his mind, but U.S. forces are reportedly already leaving their positions.