I doubt we could get support from any country, if we decided to invade Syria.
we don't have to invade. just make sure the mafiosos in power there realize we mean to hurt their interests, not occupy their useless sandtrap. We could take out their economy in a couple of hours, if I guess correctly.
The support we ultimately need is the US Armed Forces and we have that. Syria would be a mess because it is a mess, but we either are committed to the war on terror or we aren't. IMHO Syria will back down with the threat of an invasion. Iran is another issue.