The size of the residual U.S. force staying in Syria continues to grow :
The U.S. military is crafting plans to keep nearly 1,000 forces in Syria, U.S. officials said, a shift that comes three months after President Trump ordered a complete withdrawal and is far more than the White House originally intended.
Protracted administration talks with Turkey, European allies and U.S.-backed Kurdish fighters have so far failed to secure an agreement to create a safe zone in northeastern Syria, part of Mr. Trump’s plan for leaving Syria.
The U.S. now plans to keep working with Kurdish fighters in Syria, despite Turkish threats to cross the border and attack the Kurds, the U.S. officials said. The proposal could keep as many as 1,000 American forces, spread from the north of Syria to the south, they said.
Micah Zenko points out that the real number of personnel involved, including contractors, will be even higher than that:
From 200, to 400, to now 1,000 US troops. With DOD contractors and unacknowledged DOD/CIA personnel, that's probably closer to 2,500.
Trump's "withdrawal" from the Middle East and America's wars is progressing nicely. https://t.co/xQSDD9I2ft 
— Micah Zenko (@MicahZenko) March 17, 2019 
At the rate things are going, there will probably be more U.S. troops in Syria at the end of Trump’s term than there were at the beginning. There will almost certainly be some troops in Syria for many more years. U.S. withdrawal from Syria is long overdue, and it should have been one of the easiest foreign policy decisions for Trump to carry out. The fact that he can’t follow through on one of his only defensible decisions shows both his own weakness as president and testifies to his terrible judgment in selecting advisers and Cabinet officials that will fight to keep the U.S. in illegal and unnecessary wars.
The failure to withdraw from Syria was predictable and predicted, but that doesn’t make it any less discouraging. The dysfunction and lack of organization in the making of foreign policy under Trump have given the officials serving him enormous latitude to make policy according to their own preferences. Under Bolton as National Security Advisor, both the dysfunction and the influence of key officials have increased in tandem.
This is another Trump failure, but the more important thing to take away from this is that there is virtually no war so illegal or unnecessary that our political and military leaders won’t fight to continue it. The U.S. seems incapable of ending its involvement in any foreign conflict. Even when there is broad majority support in Congress to halt U.S. involvement, as there is for the war on Yemen, the White House and the Pentagon will resist to the bitter end. Even when there is absolutely no legal authority for our troops to be operating in Syria, apparently not even the president is able to bring our involvement to an end.
The continued U.S. military presence in Syria is illegal under U.S. and international law. Every day that U.S. troops remain in Syria is another day that Trump and the Syria hawks trample on the Constitution. That would be bad enough by itself, but to make matters worse the administration is breaking these laws for the sake of a policy that makes no sense and serves no American interests. A residual force of 1,000 can’t do much of anything except serve as a potential target, and the soldiers serving there are being put at risk for the sake of a mission that is both illegal and unrelated to American security.