While the US was long in opposition to federalization of Syria, demanding the nation remain heavily centralized, that seems to have been changed with the Kurdish YPG having captured massive amounts of territory from ISIS.

Now, US allies have a lot of territory to rule, and the US is looking to help them to do so, setting up infrastructures of government, and being very careful to not let the Syrian central government have anything to do with it.

That’s not in keeping with previous US positions, nor even with federalization, and Russian officials are now accusing the US of being in the process of establishing a de facto partition of Syria between the government territory and Kurdish territory.

This is likely to be a long-standing sore spot between Russia and the US on Syria’s future, as the US is unlikely to ever work with Syria’s actual government, and that’s likely to set up a new round of fighting in the future.