Winners and Losers from Trump throwing Syrian Kurds under the Bus
https://www.juancole.com/2019/10/winners-losers-throwing.html

...
It is difficult to see in what way Russia is benefited by Turkey’s incursion into northeast Syria. Russia and Turkey are more or less low-key enemies in Syria.

...

Turkey is backing some groups inside Idlib, to Russia’s dismay.

So does Russia benefit from more Turkish influence in northern Syria? No. Essentially Trump is allowing Turkey to create a long enclave along the northeast border from which it will ethnically cleanse the Kurds and then send a million of its Sunni Arab refugees into their villages to occupy them permanently. This population will be a Turkish cat’s paw and a wedge against the Kurds in the long term.

Russia doesn’t benefit. Russia wants ultimately to put all of Syria back under al-Assad’s rule, and another Turkish invasion is the last thing Moscow wants.

So what about Iran? I can’t see that this move affects Iran one way or another.
...