Its just sabre rattling IMO, but its stupid sabre rattling that I don't trust Trump to handle. We've been down the proxy war route before. What makes this stupid is that while we do have a conflict in that Russia supports the Syrian government and we oppose it, we both want ISIS to be stopped and neither want to do it ourselves. The situation is complicated and delicate, but on paper there are things to be gained here for relatively little cost. Or at least the spiraling situation could be contained with relatively few Americans dying. Its a callous view but its not like having another Iraq would be good for the locals so I think hawks and doves should both agree with the more cautious view here.
Yet here Trump is smashing the war map with a hammer. Its not like the State department is in a position to explain the various actors to him, and he doesn't listen to the IC in the first place. He's just doing this shit because of the Russia investigation. Its good that the man with his finger on the button has cable access...
Ninjaedit: also, sending in troops ourselves at this point would be a very bad idea. If Russia wanted to they would face no real diplomatic consequences for funneling training and support to whatever group they want. It would be another Vietnam/Afghanistan/Iraq all over again but probably worse than those last two. The circumstances of the Iraq War were more favorable than this: no greater power supporting Saddam Hussein (IIRC?), nowhere near the insurgent and terrorist presence that Syria has, and no Gulf War memories to drum up easy support in the opening stages.