Trump has emphasized his desire to bring American troops home, and that’s a perfectly reasonable aspiration if undertaken in a prudent way. But even as Trump abandoned the Kurds and unleashed this disaster, he was actually increasing the number of American soldiers in the Middle East — sending some 3,000 additional troops to Saudi Arabia.

So we’re sending more troops to Saudi Arabia to help a misogynist dictatorship that kills a journalist for an American newspaper, even as we betray the Kurds who have been trying to build a democratic enclave that empowers women; we’re sending troops to Saudi Arabia to confront Iran, even as we give Iran a helping hand in Syria.

This is where incoherence and inhumanity converge.

“Foreign policy is what I’ll be remembered for,” Trump boasted in 2017 to my colleague David E. Sanger. Well, um, yes.

By failing to prepare for a phone call with Turkey’s leader, and then allowing himself to be manipulated, Trump undid years of work in the Middle East. But he also is corroding the entire 75-year-old American postwar international order, built on American credibility and values. Everyone knew that the United States did not always live up to its rhetoric but also that its ideals and commitments counted for something. Until now.

I began this column with a note of praise for Obama for confronting the Yazidi genocide and saving many lives. It’s also true that Syria was Obama’s greatest foreign policy failure, and I repeatedly criticized his passivity as hundreds of thousands were killed.

Yet at least Obama was always wrestling deeply with the issues, seeking out expert opinions and trying to make the most informed decisions possible. While I questioned his judgment on Syria, I never doubted his seriousness , compassion or integrity.

Trump in contrast is callow, reckless and indifferent. What he has done in Syria is not foreign policy. It is vandalism.

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