U.S. forces in Syria are now trying to keep different parts of the “coalition” from killing each other:

The deployment is “fraught with risk,” said Robert Ford, who served as the Obama administration’s last ambassador to Syria until 2014. He is now with the Washington-based Middle East Institute and teaches at Yale University.

“That’s not a small policy change. It is a huge policy change,” he said. “We have never in our Syrian policy ever put U.S. personnel in between warring Syrian factions or to maintain a local cease-fire.”

U.S. military involvement in Syria continues to increase without debate or authorization from Congress. This traces back to the original decision under Obama to expand the illegal war on ISIS into Syria, but the latest escalation is Trump’s responsibility. Neither the Obama nor the Trump administration has ever had to justify a policy of trying to fight a war alongside mutually antagonistic forces, and neither of them has ever been forced to do so by Congress or anyone else. The president has no authority to deploy U.S. forces into Syria, and especially not to act as a buffer between forces of an allied government and proxy forces inside Syria, but we can be certain that there will be no serious opposition to it. Most members of Congress aren’t willing to criticize a war that still has broad support, and they don’t want to fulfill their constitutional responsibilities in any case.

It is questionable whether the latest deployment can even achieve its immediate goal:

Meanwhile, the U.S. presence in the area does not appear to have ended the fighting. Battles continued west of Manbij on Wednesday, according to both sides. A video posted on social media Wednesday morning showed U.S.-armed Arab fighters allied to the Kurds using an antitank missile to destroy a military vehicle belonging to the Arab fighters allied to Turkey.

An anti-ISIS “coalition” that includes both Turkish and Kurdish forces has never made sense, and this would seem to confirm it. Other members of the “coalition” are more concerned with their own agendas, and the U.S. is stuck trying to balance the competing interests of forces that would sooner be fighting each other than they would the supposed common enemy. The U.S. should never have become involved in this war, and it ought to be looking for a way to disentangle itself rather than become even more involved.