For more than a decade, the United States has sought to keep out of Syria's political debacle, seeing no viable partner. Islamist rebels' toppling of strongman Bashar al-Assad has forced a change of tune -- and a debate over just what US interests are.
Donald Trump, who returns to the White House in little more than a month, on the eve of Assad's fall called Syria "a mess" and stated in his plain-speaking style that the United States should not be involved.