What gives?

One theory is psychological: From Putin to Erdogan to Kim, the president has a thing for authoritarians in the mold of his father. Does he long for the power these men wield — or does he long to yield to their power?

A second theory is that Trump is cultivating his extensive business ties in Turkey. This week, my colleagues David Kirkpatrick and Eric Lipton detailed the striking ways in which Trump’s son-in-law, Jared Kushner; Erdogan’s son-in-law, Berat Albayrak (who happens to be Turkey’s finance minister); and the son-in-law of leading Turkish tycoon Aydin Dogan (who owns the Trump Towers in Istanbul) have cultivated a cozy backchannel. The result has been weak sanctions for Erdogan’s misbehavior and quick capitulations to his demands.

A third theory is that Trump is pursuing a political strategy. He sees his slogan of “ending endless wars” as part of his re-election appeal, and Erdogan can help him do it by filling a vacuum created by his withdrawal from Syria, with no regard to the people betrayed in the bargain. Add to this the strategic rationale that it’s better to have Turkey as a truculent ally within NATO than as a dangerous foe, and you have something that almost resembles a normal explanation for policy.

These theories aren’t incompatible: As with so much else in Trump’s world, personal psychodrama, commercial venality, political self-dealing, and moral folly freely mix.

But they’re also a reminder of how debased policy-making has become during this presidency.

Turkey has long been of immense strategic importance to the West — as a check on Russian expansionism and Islamist fundamentalism; and as an inspiration for secularism and modernization for the Muslim world. Erdogan, a longtime Islamist and recent ally of Russia, is the most dangerous leader it has ever had.