So far the end game in Syria has played out in an entirely predictable way. All of Aleppo is back in the Syrian government's hands, that decisive victory for President Bashar Assad and his Russian backers has been followed by a cease-fire, and the Russians are now organizing a peace conference in Astana, Kazakhstan, for later this month.
The one surprise is that Turkey, long the rebels' most important supporter, will be co-chairing the conference. This means that Turkish President Recep Tayyip Erdogan has made a deal of some sort with Russian President Vladimir Putin, for Astana is clearly going to be a Russian show. (America has not been invited, and Saudi Arabia probably won't be asked to attend either.)
So what kind of deal has Erdogan made with Putin? The details may well have been fudged, for Turkey has not yet renounced its long-standing insistence that Assad must step down as the Syrian leader. But it's pretty easy to figure out most of what is going to be on the table in Astana (assuming the cease-fire holds until then).