I hear a lot of people criticising Trump for the Syria thing, but I don't see any alternative solutions being offered. The problem is that this was a time bomb where the US was acting with NATO ally Turkey in Syria.
The Kurds were good for being proxy troops for the US, but they were a problematic ally. First off, the Turks (and US) lists them as being terrorists. Secondly, the Kurds' loyalty was to themselves and their goal of a nation. That was a goal that the US could never honestly promise. And while the Kurds will happily fight anyone: they won't do it for someone else unless the someone else is going to protect them.
That leads to problem one: the Kurds will shift loyalties to who ever will protect them. They were fighting with Assad early in the conflict. The US lured them away, but the Kurds made it clear that they would switch back to Assad if the US stopped protecting them. The problem is that the military isn't the body that makes the decision: the politicians are. The military isn't supposed to question: it's supposed to obey.
And the military can't make too many friends in a place where there are rapidly changing allegiances such as the Syrian Civil War. Learn a lesson from the Kurds, your loyalty is to yourself first.
The Kurds were an American ally against ISIS, not Turkey. The United States made no commitment to protect the Kurds
against the Turkish army, much less assist them in maintaining a degree
of independence in northern Syria that I know about. The United
States was entitled to pursue its own interests in the region without some form of formal agreement. Neither Trump nor Obama defined those
interests in a way that would justify a deepening military engagement in
Leaving the few soldiers in the Kurdish zone endangers American lives. The Generals who felt strongly could have disobeyed orders if they felt such a strong tie to the Kurds, but then the blame would fall on them for endangering their troops in a Turkish invasion.
Next problem: the NATO Treaty. The Treaty is a formal agreement, unlike whatever was between the US and Kurds. The existence of a Treaty ruled out a military response of any sort. A no-fly zone would be a no-no. Nothing says betrayal like shooting down an Ally's airplane.
On the other hand, Congress could declare war on Turkey if they feel as strongly as they purport to, but they won't.
The only real options are economic or diplomatic. The only real difference between what I would have done and what Trump did would have been to get international action to prevent the Turkish invasion. I also would have begun working on an exit strategy earlier. The Turkish invasion of Syria was not something which was in any way a surprise, yet no one did anything to prevent the problem.
The big problem is that there is a lot of bluster here. Congress is blustering. The Generals are blustering. The Turks are blustering. Trump is Blustering.
It's easy to play the blame game, but this was a disaster waiting to happen. Too many people failed to act to prevent the problem.
At this point, the US should take a deep breath and look at how it got into yet another mess.