Trump may believe that he’s doing the right thing, that abandoning the rest of the world’s problems will “make America great again.” He doesn’t realize that America’s might and wealth depend, in large measure, on the cooperation it receives from others—either offered or coerced—in pursuing its interests around the world…

Trump has made a practice of abrogating treaties, filching on commitments, and alienating allies, but, more than any single act, the betrayal of the Kurds should tell everyone that—as long as Trump is president and, who knows, perhaps beyond—there is no reason to trust the United States on anything…

In one sense (and Trump is probably thinking along these lines), this might be for the best: the Middle East is a mess; if Putin and Assad can solve it, fine—and if they can’t, that’s fine too, as long as we’re out of there.

But in another sense, this sort of thinking is delusional. First, we’re not getting out of it. Second, the rest of the world is watching. Especially with all the other troubled aspects of its relationship with Trump just now, Ukraine must be rethinking the wisdom of relying on the United States for assistance. The eastern nations of NATO, especially the Baltics, would have good reason to look elsewhere for security guarantees. Already, traditional U.S. allies in Europe and Asia are exploring agreements, on security and trade, outside of Washington’s orbit.