From the start of the Syrian Civil War, Western nations have been more or less universally agreed on one point, that Syrian President Bashar Assad has to go. Four years in that mantra is still being repeated, but with a lot more caveats than it used to.
The latest round of comments from Western officials could be summed up as “Bashar Assad has to go, but,” with Turkish President Recep Tayyip Erdogan, a former Assad ally turned outspoken Assad opponent, saying that the “process” by which Assad is eventually removed from power could give Assad a role, even though “nobody envisages a future” where he isn’t gone eventually.
German Chancellor Angela Merkel similarly insisted any talks about Syria should realistically include Assad, saying the West has to speak with all actors in the region if they want to accomplish anything. That Merkel didn’t include the requisite number of “Assad must go” comments in her speech sparked some backlash, with suggestions that any talks involving Assad would mean no rebels would participate.
Which is true primarily because the Western nations that have been backing those rebels keep telling them not to participate. The Russian government has tried to get such “unity transitional government” talks going more than a few times, and the lip service initially given by everyone is scrapped pretty quickly when rebels who already agreed to participate suddenly change their tune after comments from some official in the US-led coalition.
So long as the US remains on the outside looking in on this realization that their rebel allies are getting smaller and smaller, it’s probably going to keep them out of any efforts to help the similarly faltering Assad government fight the groups that are actually growing, primarily ISIS. By the time everyone gets in board, however, it may be too late to matter, and ISIS will be so much larger than everyone else in the country that no amount of unity will be competition for them.