Secretary Mattis claims not to understand why pro-regime forces advanced on U.S.-backed rebels in eastern Syria:

In Washington, Defense Secretary Jim Mattis described the situation as “perplexing,” and said he had “no idea why they would attack” the base. Both Russian and Syrian-aligned forces on the ground had long known the U.S. and allied forces were there, he said.

Perhaps Mattis is only feigning confusion here, but it isn’t encouraging that the head of our Defense Department claims not to know why forces aligned with the Syrian government might want to attack a base where the enemies of that government are located. They attacked the base because they “had long known the U.S. and allied forces were there.” They oppose the presence of “U.S. and allied forces” there. This should be clear by now. If our top leaders don’t know something as basic as this about the situation they are putting our soldiers in, that is deeply troubling. Mattis also “denied that the attack and the U.S. response constituted American engagement in the Syrian civil war,” but this is preposterous. By providing support to armed groups inside Syria and deploying our own forces alongside them, the U.S. is taking sides in the Syrian civil war whether our leaders want to acknowledge that involvement or not. By attacking pro-regime forces and killing dozens of their men, the U.S. has committed acts of war against another government on its own soil without Congressional or U.N. authorization.

As the threat of ISIS recedes, it becomes increasingly difficult use that threat to justify a U.S. military presence inside Syria. The pretense that an open-ended mission in Syria is solely aimed at opposing ISIS is not credible when U.S. officials explicitly state that an indefinite U.S. military presence is also intended to deny the Syrian government and its allies control over parts of Syria. The Syrian government and its allies did not try to stop U.S. intervention in Syria when it began in 2014, but they have never agreed to our military presence. As it happens, the Syrian government and its allies are correct when they describe our military presence there as illegal. Secretary Mattis isn’t able to counter those claims because there is absolutely no legal justification for having our troops in Syria and there never has been.

The smart thing to do now is to remove U.S. forces from Syria as soon as possible to ensure that there are no further clashes like this. If the Trump administration doesn’t do that, it will be inexorably pulled deeper into conflicts that serve no American interest.