A man wakes up one morning and thinks he's back in the Middle Ages. Russian State Prosecutor Vladimir Ustinov, the front page of the Russian newspaper Izvestia reports, has decided to launch an official investigation of the Shulhan Arukh, the definitive compendium of Jewish law written in the 16th century by Rabbi Joseph Caro and used to this day - generally in an abbreviated version - as a standard reference book by Orthodox Jews.

Prosecutor Ustinov has already summoned Moscow rabbi Zinovy Kogan, chairman of the Congress of Jewish Organizations, for questioning in order to determine whether the Shulhan Arukh should be banned for "racist incitement." He took this action after receiving a letter last January, signed by 500 patriotic Russians, calling the Jewish religion "anti-Christian and inhumane" and demanding that the Shulhan Arukh be banned.

You read and rub your eyes and read again. And still it's hard to believe.

When did something like this happen before? Well, the first time was in 1240, when Pope Gregory IX, after receiving a formal denunciation of the Talmud as "blasphemous" and "pernicious" from a French Jewish apostate, ordered all copies of it seized and an investigation of it undertaken. At a public inquiry held in Paris in the presence of King Louis IX, the Talmud was found guilty. On June 17, 1242, all confiscated copies of it were burned, as part of 24 cartloads of Jewish books, in a large bonfire.

State Prosecutor Ustinov - indeed, the government of Russia that has not immediately acted to remove him from office - can be proud to belong to a time-honored tradition. Perhaps we can look forward to bonfires in Moscow sometime soon. You rub your eyes and read again.

Not, of course, that the Talmud - or the Shulhan Arukh, for that matter - is entirely free of anti-Gentile remarks. Given the world's treatment of the Jews over the past 1,500 years, it's surprising that there aren't more of these. Yet if we're going to start eliminating religious books for their hateful passages, why start with the minor case of Jewish ones? Let's first burn the New Testament and the Koran for viciously consigning all nonbelievers, Jews included, to the eternal torments of hell. (Which is a punishment, incidentally, that Jewish tradition never invoked on Christians and Muslims.)

But, of course, even to make this kind of argument is to stoop to taking the intellects of State Prosecutor Ustinov and the 500 letter writers - among which were Russian authors, mathematicians, and former international chess champion Boris Spassky - too seriously. One doesn't argue logically with rabid idiots. One fights them as dangerous enemies must be fought, with no holds barred.

The scary thing is that once again, 50 years after the Holocaust, the Jews have so many enemies. And make no mistake about it: They are dangerous.

Nor are all of them primitives out of the Middle Ages. Some are very suave, very cultivated gentlemen. They wear three-piece suits and they speak with Oxonian accents and they say things like "bloody nuisance" and "spot on." Some are even leaders of the Anglican Church.

You may have noticed it. The international advisory body of that church voted last Friday in London to urge its congregations, which have 75 million members worldwide, to disinvest in Israel because of its "oppression" of the Palestinians.

These are not benighted Slavophiles. They are sophisticated High Churchmen. With them one can argue. One can say: "Of all the world's 'oppressing' countries - China, which oppresses Tibet; India, which oppresses Kashmir; Russia, which oppresses Chechnya, et cetera, et cetera - the one you've decided to boycott as good Christians is the country of the Jewish people? The country of the same Jews whom you Christians have hounded throughout your history and whom you Anglicans and Englishmen watched as they were slaughtered by the millions in Europe while you did nothing to rescue them and barred the gates of Palestine and England to those of them who might have fled? Have you no shame? No honor? No awareness of your own appalling hypocrisy?"

No, they have no shame, no honor, no awareness of their own appalling hypocrisy. And they are anti-Semites no less than State Prosecutor Ustinov and his 500 imbeciles. In fact, they are State Prosecutor Ustinov's allies.

This cannot be said too often. In an age in which a Jewish state's right to exist is still not recognized by much of the world - in which tens of millions of Arabs and hundreds of millions of Muslims regularly clamor for its destruction - in which a Muslim country now in the process of arming itself with nuclear weapons openly refers to it as an outlaw creation that must be wiped from the face of the earth - anyone deliberately undermining this state's legitimacy, even if he wears a respectable English clergyman's collar, is contributing to another possible genocide of the Jews.

Criticism of Israel? By all means. This is perfectly legitimate. So is concern for the Palestinians. But disinvestment is not criticism. It is an attempt to turn Israel into a pariah state. And Jews, having been treated as pariahs by Christian civilization since the age of Constantine, know exactly what this means.

Half a century after the Holocaust, a new war against the Jews has been declared. We are only now - innocents that we have been, lulled by the world and our own wishful thinking into believing that widespread Jew-hatred is a thing of the past - waking up to its true dimensions.

It is not a war that we Jews will necessarily win, although it is not one that we can afford to lose. But we, too, have our allies and we are fortunate that they are more intelligent than our enemies. We have to impress on them that the fight is not only for us but for a sane world that has not completely lost its moral and intellectual bearings.