It's time to call Turkish Prime Minister Recep Tayyip Erdogan what he is: a semi-unhinged bigot.

Optimists have argued, these past few years, that Erdogan's anger at Israel was motivated by a genuine sense of grievance over the notorious 2010 flotilla incident. The flotilla, you'll recall, was a project of pro-Hamas Turkish activists that was meant to break what they termed an Israeli blockade of the Gaza Strip. Israel's attempt to stop the flotilla ended in the deaths of eight Turks and one Turkish-American.

The Turks demanded, among other things, that Israel apologize for its handling of the affair. Israel resisted for three years, saying that its soldiers were attacked by the Turkish activists when they boarded the ship, and that Israel had the legal right to stop the flotilla from approaching its waters. Nevertheless, the Israeli response was horribly botched, and this year, Israeli Prime Minister Benjamin Netanyahu, coaxed and cajoled by President Barack Obama, picked up the phone (with Obama sitting right there with him) and apologized to Erdogan for the unnecessary deaths. This apology was supposed to usher in a newer, quieter era in Turkish-Israeli relations.

Except that Erdogan has Jews on the brain, and once you get Jews on the brain it's hard to get them off. So the other day, in talking about the strife in Egypt, he said: "What is said about Egypt? That democracy is not the ballot box. Who is behind this? Israel is. We have the evidence in our hands."

The evidence for the assertion that Israel was behind the violent suppression of the Muslim Brotherhood? Erdogan himself offered none, but an aide later said that the prime minister was referring to an Internet video Erdogan saw in which the current Israeli justice minister, Tzipi Livni, and the famous French-Jewish philosopher Bernard-Henri Levy, were speaking at a news conference in 2011. In the video, BHL, as he is known, expressed opposition to the Muslim Brotherhood's ruling Egypt.

And that's it. The prosecution rests. A Jewish philosopher from France (albeit one with great clothes) says on television that he doesn't like the Muslim Brotherhood, and that's sufficient proof for Erdogan.

Now, if someone were to go on television in the U.S. and assert -- based on the aforementioned single piece of "evidence" -- that the Jewish state was behind the chaos in Egypt, well, that person would soon find himself with limited opportunities to offer further commentary (even on Al Jazeera, I assume). But we're talking about the prime minister of a major American military ally and the leader of a nation of more than 70 million people.

And this isn't the first time, of course. Just recently, Erdogan blamed widespread demonstrations against his government on the "interest-rate lobby," which is up there with "rootless cosmopolitans" and "dual loyalists" as an all-purpose euphemism for Jews. (His deputy, Besir Atalay, made it plain when he blamed the protests on "the Jewish Diaspora.")

Although not very good at making friends, either in Europe or in the Middle East, Erdogan is known as a very smart man. Yet anti-Semitism is making him stupid. As Walter Russell Mead of the American Interest magazine says, those who are burdened with anti-Semitism are unable to discern cause and effect relations in complex social settings. If I were an investor in Turkey, I'd keep this mind.

You see what I did there, right? A year from now, Erdogan -- if I'm lucky -- will cite this post to explain whatever affliction is afflicting Turkey at the moment.

(Jeffrey Goldberg is a Bloomberg View columnist. Follow him on Twitter.)