While everything written here is accurate, I think there is more to this story. As I have written here and just responded to another article aghast at what has happened, Trump is insane but predictable:
While this is certainly a blunder in international relations the question is really, as you note in this article, Trump’s motivation for this. His ignorance and impulsivity is well known but we should not forget his single minded focus on his self interest. Nothing else matters much to this type of psychopathic narcissist.
The most significant aspect of self interest for these people is their own protection and continued ability to enhance their status in the eyes of people they fear. In short, Trump blew it, I think, with Putin by screwing up in the Ukraine which Putin wants back in Russia.
By attempting to extort the new Ukrainian president for personal political benefit he made one of Putin’s goals harder to accomplish. This could well explain the sudden ‘impulse’ to backstab the Kurds and turn Turkey lose on them.
Trump gave Erdogan what he wanted while supporting his own efforts to protect his two hotel properties in Turkey and handed Syria to Russia. Russian troops (police?) are already patrolling the Syrian/Turkish line in Syria. The Russian movement of troops was very quick. Russia owns this now and the Kurds are now in a Syrian alliance.
This did nothing good for the US, started murder of the Kurds, but covered Trump’s ass by delivering Syria to Putin. I suspect that Trump had promised this to Putin early on in Helsinki or one of his ‘unrecorded’ calls, and the obligation was being called last week by Putin noting Trump’s, probably terminal, Ukraine disaster.
When Trump leaves the White House he will face criminal charges on many fronts. Even if Pence pardons him that would do nothing for the Russian justice that would descend on Trump for failing to deliver what he had promised.
I suspect at some point in the next few weeks pieces of these deals with, hopefully verifiable proof, will come out. Trump’s criminal gang is coming apart and a steady stream of his people will start to squeal as his power evaporates.