If the US tries to topple Assad by sending in the military, the worms might not be able to get back in the can. However, Trump is clearly in Putin's pocket, so an armed confrontation between US-Russia looks unlikely at this point. Trump unwittingly doing more for world peace than Obama ever did, lol.
But if Trump gets ousted from the WH, and Pence gets in there, or Ryan, or even Hillary, John McCain will be walking around with a torpedo in his pants just waiting to spearhead the call for war.