Should Iran move to push Iraq and Syria into more of a vassal status (they are not quite there yet) the US could easily close the Iraq / Syria border and move to secure Northern Iraq with Kurdish support. Overland supply would come through Jordan and Turkey would without any doubt do another backflip in favour of which ever power seems to be top dog on the day.
Our pro-Putin friends know this BUT is Putin in a position to make Khamenei's nutters behave? Rouhani can't do it so I don't like Putin's chances.
Moving forward, collaboration between the US and Russia can be both subtle and long term should both powers actually seek Syrian empowerment as an outcome to counter the nefarious agendas of surrounding regional powers.Facilitation could take the form of closer economic interfaces between the Damascus Government and the Northern Administration as a starting point.
Leaving MSM and realpolitik commentary about Assad the person to the side for the moment, the last thing either Khamenei or Erdogan would want to see is Syrian nationalism being supported by the SDF in alliance with the SAA and NDF while Russian and US forces remained in-situ. Russia and the US need to counter this agenda.
Should Iran decide to "behave" it will retain economic influence and residual political influence (to a degree) . The problem for Iran is that Khamenei's clowns don't know how to behave.
