The U.S. military presence in Syria is set to continue indefinitely :
The Trump administration is expanding its goals in Syria beyond routing the Islamic State to include a political settlement of the country’s civil war, a daunting and potentially open-ended commitment that could draw the United States into conflict with both Syria and Iran.
The U.S. already has at least 2,000 troops  in Syria, and that number is likely to keep growing as the U.S. entangles itself more deeply in that country. An open-ended deployment in the territory of an unfriendly government that is supported by Iran would seem to be a recipe for a pointless and easily avoidable conflict. At best, it is a waste of resources and manpower in a place where the U.S. has little or nothing at stake. At worst, it is the start of a steadily expanding mission that will embroil the U.S. in yet another futile war. That will do nothing to make the U.S. or its allies more secure, and it could contribute to further instability in the region.
The justification for this continued presence is bizarre:
An abrupt U.S. withdrawal could complete Assad’s sweep of Syrian territory and help guarantee his political survival — an outcome that would constitute a win for Iran, his close ally.
To avoid that outcome, U.S. officials say they plan to maintain a U.S. troop presence in northern Syria — where the Americans have trained and assisted the SDF against the Islamic State — and establish new local governance, apart from the Assad government, in those areas.
In other words, the U.S. needs to keep American soldiers in harm’s way out of fear that the government of Syria might reestablish control over the rest of its own territory. That is so ridiculous that it can make sense only in the context of our warped foreign policy discourse. There is no discernible American security interest that demands that the U.S. keep part of Syria from being returned to the control of its government. It is certainly not the responsibility of our military to “establish new local governance” inside Syria. The real reason for the open-ended mission seems to be to compete with Iran for influence inside the territory of its ally, and that is as unnecessary as it is foolish.
It almost goes without saying that a U.S. military presence in Syria for any purpose has no legal justification whatsoever and has not had any for the last three years. Congress has never authorized military action there against ISIS or pro-regime forces, the Syrian government has never given the U.S. permission to operate on its territory, and our military presence there has absolutely nothing to do with self-defense. Keeping U.S. forces in Syria for years to come is the very definition of mission creep. Congress should insist on the withdrawal of U.S. forces from Syria as soon as possible.