Be afraid. Be very afraid. That was the message I got from a PBS documentary on anti-Semitism in the Muslim world that aired Jan. 8 on WNET.

But that didn’t keep me from asking: Be afraid of what?

The documentary, produced by Oregon Public Broadcasting, was called Anti-Semitism in the 21st Century: The Resurgence, but could more accurately have been titled Muslim Hatred of Jews — Anti-Israel or Anti-Semitism? It offered a quick recap of both European Christian anti-Semitism and a fairly evenhanded summary of Israel’s birth and the Arab-Israeli conflict. The two come together in the comments of talking heads, Jews and Muslims alike, who agree that the Muslim world has become infected with classic Christian and Western fantasies about the Jews. Princeton’s Bernard Lewis explains the distinction between old-school Muslim antipathy to the Jews and new: The latter is colored by Christian notions of the Jews as satanic.

The most telling piece of evidence is the mass translation and distribution of The Protocols of the Learned Elders of Zion, the 19th-century Russian hoax that posits a worldwide Jewish conspiracy. The documentary says the tract is widely available throughout the Muslim world. The point is echoed by person-in-the-street interviews in Egypt and Syria.

But in the age of the Internet and satellite television, the Muslim world puts its own particular spin on the Protocols by incorporating its lies into lavish multi-part television mini-series like Horseman Without a Horse and The Diaspora. The shows feature graphic reenactments by unconvincingly bearded “Jews” of Protocols-like meetings and, in a particularly gruesome scene from The Diaspora, a blood-libel. Both series have been broadcast during Ramadan, when families throughout the Muslim world are known to gather around their television sets. It’s like A Charlie Brown Christmas, except the Peanuts gang gets murdered and baked into a batch of matzas.

Having presented the evidence for the resurgence of anti-Semitism in the Muslim world, the documentary goes on to ask why. There is agreement among the experts, although not unanimity, that the anti-Semitic expressions are a reaction both to the emergence of Israel and the powerlessness felt by Arabs after their humiliating defeat at the hands of the Israelis. Former Washington Post Mideast correspondent David Ignatius, usually a careful and fair-minded commentator on the conflict, comes perilously close to blaming the Jews when he cites the “unwise and unjust actions” that have enraged Palestinians and their supporters.

Other experts chime in, saying despotic Muslim governments whip up a confection of pro-Palestinian sympathy and anti-Jewish fantasy in order to divert attention from their countries’ own internal problems.

The documentary was better at explaining the extent of anti-Semitic feeling in the Muslim world than its effect, leaving it up to viewers to ask just what sort of threat this almost medieval hate-mongering presents to me and my people.

So am I afraid? In my own corner of the world, where anti-Semitism is vestigial and Muslims without power, not very.

But then I think of Iran, led by a president who has urged that Israel be “wiped off the map” and is inspired by mullahs who seem theologically prepared for their followers to absorb the mutual slaughter of an exchange of nuclear missiles.

I worry about Israel, which has reached a consensus about how to end its blood-soaked conflict with the Palestinians but is stuck with a “partner” whose people prefer to die among those they demonize rather than accept a state that is less than their leaders and supporters tell them they deserve.

I worry about the Jews of Europe, now home to some 21 million Muslims, many of whom are disenfranchised, unemployed, and rootless in their adoptive countries. Academics may debate whether the new anti-Semitism is merely anti-Israel fervor wrapped in a convenient rhetorical package, but you’ll forgive the Jewish shopkeeper who doesn’t want to discuss semiotics when a stone comes crashing through his window.

And finally, I worry for the entire world, whose greatest challenge is defusing the rage and nihilism of the Arab street. If so many millions can be swayed by obvious forgeries and historical libels, what other fantasies are they being fed and are they swallowing? Watching a hijab-wearing toddler call Jews “pigs and monkeys” or a Jordanian college student parrot lies about the Jews who were “warned” about 9/11 leaves me in despair that anything can alter the course the Muslim world has chosen for itself — and us.