While I have always had misgivings about the role of the US in the Syrian civil war, I think that Trump's sudden planned withdrawal of American military personnel from Syria will be a disaster... Daesh hasn't been completely defeated, the Syrian government isn't exactly a 'good' player in the conflict. More worrisome to me is the utter selling out of our Kurdish allies. Out of the peoples of the current Middle East, the Kurds seem to align best with American values, embracing religious pluralism and women's rights to a greater extent than their neighbors.
So now, the Turkish army is massing at the Syrian border, our nominal NATO allies moving against our allies of the recent conflicts in the region. This is the same abandonment of allies that I mentioned in my post about Bush 41, who suggested to the Shiite marsh Iraqis that they should rise against Saddam Hussein, then abandoned them to get slaughtered. This sends a horrible message yet again- the United States is not to be trusted, so why ally with the US?
Any withdrawal from the theater of war should be well-considered, but the erratic, sudden actions of an irresponsible executive will do permanent damage to our standing in the world.