That's not the only reason - also because Iran ordered him to protect their guy in Syria.
You are right. But plenty of Freepers say they are there to protect Christianity or defeat ISIS, which is nonsense. They have even worked with parts of ISIS in cases. (ISIS is not the monolith most Americans think) And Russia is not the reason ISIS is in bad shape today - that is because the nature of ISIS was doomed to retract and decline. I appears the only reason for the US is there is to thwart Russia. And that’s piss-poor foreign policy.
I actually disagree with that. The U.S. actually has no coherent policy in Syria. We are only there because we pathologically cannot help ourselves from getting involved in the Middle East. To that extant Obama and Trump basically have a similar confused, incoherent policy there. We should just be out of there, and thank our luck that it's not our problem.
“They have even worked with parts of ISIS in cases”
All sides have worked with ISIS in Syria, to include the United States.
And yes, the only difference between Obama’s and Trump’s policy there is the fact we made significant gains against the Caliphate.
But we are still in bed with corrupt, murderous jihadis.
And for no good reason, at least not one that could wildly be construed as a national interest.
The ONLY interest the US has in Syria is stability. And that is best achieved by supporting Assad in his effort to gain control over the entire country.