“Potentially Saudis could manage the airspace over the Kurdish enclave after a US withdrawal. They have a modern air force, and have had PATRIOT air defense systems for a quarter century.”
Who are the Saudis gonna shoot at? Turks? Syrians in their own airspace? God forbid, Russians? If the Saudis are invading via air, doesn’t Assad have the right to shoot an S-300 at them? The Kurds should make a truce, swear loyalty to their own Syrian government and that should keep the Turks away.
“swear loyalty to their own Syrian government and that should keep the Turks away.”
That did not work for them when tried in Afrin.
Turks invaded, overwhelmed the Kurds, Syrian Arab Army and their Iranian militias, and unleashed their Arab militias (many former ISIS members) on the civilian Kurdish population.
The Turkish military is more than an order of magnitude greater than the remaining rump of the Syrian military.
One of the main end state scenarios for Syria has long been a semi-autonomous Kurdish Region within the Syrian State, like the Kurdish Regional Government withing Iraq.
The Kurds will always need protection from Turkey. Both the Kurds and the Regime (common usage) have gone to lengths over the many years of war, to not burn the bridges between them.
It is a pretty likely outcome, unless foreigners support Kurdish aspirations.
The risk would be that the entire country is then consolidated as a Satrap of Iran.