Without giving an opinion, just a reminder of a few facts:

The Constitution gives Congress the sole authority to declare war.
US troops/CIA agents have been in Syria for over a decade, participating in a war against it's current government.
For the first four or five years of that, our involvement wasn't even public, or known to the entirety of Congress.
Congress did not declare war on Syria or Assad, either prior to or during that time.
Troops on the ground in an active war zone, especially working in concert with an army they're training, funding, and arming... are at risk.
Not a single one of the three US Presidents involved were impeached for this.