Despite having been terrified since the election (and for a significant portion of the campaign, too) of the very real threat of war in both countries, I'm honestly going to go with "none of the above."
What little legitimacy he had is thoroughly exhausted. The GOP hates him, world leaders think he is a joke, he's under investigation by the FBI and the only person who actually seems to credit him with anything except complete idiocy is himself (and a small portion of the American public, but let's not go into that now).
Who is going to join a coalition? What makes you think he has the wherewithal to even bother trying to draft a dodgy Blair-style dossier? I totally see him trying to start a war, but I just don't see it getting anywhere at all.
As far as Iran goes; yeh, not seeing that one either. Sanctions? Sure. Drone/tomahawk strikes? Probably. Boots on the ground? Nah.