Ed Husain doesn’t think Assad is danger of being overthrown, but adds this:

Already, calls for military intervention are being made by Syrian opposition activists in meetings at the White House and US state department.

If that’s correct, that is a cause for concern. If a lot of Syrian activists begin calling for military backing, that will remove one significant obstacle on the path of escalation. However, everything I have seen so far points in the other direction. Syrian opposition activists in Syria have usually been explicitly rejecting military intervention. If there have been activists here in the U.S. agitating for military action, it appears that they are speaking for themselves and not representing what most of the Syrian opposition wants. That is just as well, since there appears to be no interest on the part of the administration or any European allies to start another war.