IT MAY NOT SEEM to be a Christmas topic, but in a way none could be more so. I am talking of anti-Semitism.

Few things are more depressing now than the evidence, reported in the newspapers from week to week, that anti- Jewish feeling persists across the world. Not only persists, indeed, but seems to be increasing. Century after century, the virulence goes on, even as we sing carols to a Jewish baby.

Here are just a few headlines of the past three months: "Anti-Semitism Is Seen in Some German Texts;" "Ethiopia's Black Jews, a Periled Community;" "French Jewry's Well-Grounded Fear;" "Anti-Semitism Goes Respectable" -- that of America. And there are the sentences beyond the headlines: "Once again, Jews are the victims. This time, the Falashas;" "Austria's is an anti-Semitism without Jews ...."

Year in and year out, it goes on and on. We can rely on our Christendom for this. Wherever there are difficulties, take comfort and blame -- why, of course, the Jews. It's the done thing, after all; age after age, we've done it. In the ancient world -- vilify the Jews; in the medieval world -- vilify the Jews; in the modern world -- vilify the Jews. Why expect it, in the future world, to be different?

Just vilify them, mind you, not crucify them. We have grown namby-pamby since the Holocaust. The most depressing things in today's stories is the constant refrain: "Of course the anti-Semitism today is not militant." That somehow seems to make it all right. We don't actually make lampshades out of Jews' skin now -- we are more civilized than that -- so we have our sport with them with a free conscience.

The facts and figures can read so smoothly. After the bombing of a Paris synagogue last October, Louis Harris conducted a poll throughout France. One Frenchman in eight thinks that there are too many Jews in France; one in 10 feels that Jews are not "as French" as other citizens. It is easy to be numb to such figures -- what meaning is there to them? -- until we recall the years of Vichy.

But if we feel bland about the Frenchmen in the poll, we have only to remember that, in the days before that one publicized bombing, two other synagogues, a Jewish school, a Jewish day-care center and a Jewish monument were all machine-gunned in Paris. (That is only part of the catalogue of violence.) The violence is the work of terrorists and neo-Nazis -- yes -- but what is the soil in which they breed?

So one's eyes stray from country to country, absorbing the stories of what now seems to be universal. The downplaying of the Nazi treatment of the Jews, the revival of neo-Nazism on the right, the emergence of an anti-Zionist, anti-Israel feeling on the left, which all too easily finds an anti-Semitic accent. The ingredients, old and new, are there. They make a powerful and virulent mixture.

Whether it is a response to the need for Arab oil, or to the wish for a settlement in the Middle East, pro-Arab sympathy is now more widespread than before. There can be no honest person who will not admit that, at the back of all our consciousnesses, lies one simple, obvious, if unspoken solution to our problems in the Middle East. Dump Israel. For the sake of oil and peace, abandon this one Jewish state.

There is much to be said for understanding the position of the Arabs. But the distressing fact is that an impatience with Israel, even when it is justifiable, is all too easily translated into anti-Jewishness. The most reasonable criticism of Israel rings in its train all the code words by which it is transmuted into anti-Zionism and then into anti-Semitism with each step barely recognized.

Black and Third World identification with the Arabs feeds a new strain into old attitudes, and in turn the left here and in Europe identifies with the Third World and the blacks. Thus a new strain from the left is fed into the old. Rationalizations of anti-Semitism are now heard in quarters where they were not known before. Not only heard, but left unchallenged. Not only left unchallenged, but given some respectability. Anti-Semitism is ceasing to be a mark of disgrace.

It is all very well suddenly to see the Poles as heroes. I am the last person to deny the recurring vitality which they keep on displaying in their history. But they have never been, under right-wing or left-wing regimes, very reliable defenders of civil freedoms. They have also been in their history, under right-wing and left-wing regimes, one of the most anti-Semitic nations in Europe.

Just as Austria, even with its Jewish communities shrunk to a few thousands, is still anti-Semitic, so is anti- Semitism also strong in Poland, with its Jewish population also shrunk. When such hositility to a race of people persists, even in countries where there is not now a population to provoke it, one is talking of a terrible evil, against which we dare not let down our guard.

This is not the place to examine the causes and sources of anti-Semitism, a subject which led even the late philosopher Hannah Arendt into an unpleasing ambivalence. What matters is that outbursts of anti-Semitism have consistently heralded either totalitarianism or simply the collapse of a political and even a moral order. Once the Jews get it in the neck, as history amply shows us, our turn is not far behind.

Anti-Semitism both feeds on and then engenders notions of conspiracy. If we tolerate ideas of Jewish or Zionist conspiracy, ideas of other conspiracies grow in the soil. If the Jews are conspiring, who may not be conspiring? Once release the idea that some difficulty which besets us is the result of a plot, and we quickly find that the existence of a plot can explain all our difficulties.

I do not see how anyone can deny that the atmosphere is now thick with theories of conspiracy. We do not just confront the Soviet Union, it seems, we confront everywhere a Communist conspiracy. There are not just groups of terrorists, with very different aims, and some of them loosely associated, there is a worldwide terrorist conspiracy. Cuba is not simply a nation -- and a nuisance -- it is itself a conspiracy.

The whole of Central America and the Caribbean is one gigantic conspiracy, and not just a cluster of small nations and islands, each with its particular as well as general problems. If things do not go America's way anywhere in the world, then we are told that there is a conspiracy. There are conspiracies, also, here at home. If the administration's economic policies fail, the old Wall Street conspiracy is blamed.

There is a conspiracy to prevent babies from being born, a conspiracy to keep religion out of schools, a conspiracy to teach pornography to first-graders, a conspiracy to deny the right to bear arms, a conspiracy to make us all homosexual and a conspiracy to erase the story of our genesis. It is hard to remember a time when the air has been so thick with stories of plots, and our minds given so few rational explanations of what is going on around us.

In at least one of its aspects, anti-Semitism is an escape from complexity. All conspiracy theories are efforts to find tidy explanations of the untidy world. If something goes awry somewhere in the world, someone must somewhere be issuing secret protocols. Our politics are, day by day, being reduced to simple responses to situations which are simply described.

Anti-Semitism is a simple explanation of anything which we find too complicated. But this is true of all ideas of conspiracy. And those who imagine conspiracies must themselves become conspirators. Their theories can be sustained only by unrelenting, far-into-the-night dredging over old facts to find new meanings in them. If the conspirator is clandestine, so is the theorist of conspiracy.

Closeted in his room, wrapped in his obsession, he will find the proof. Meanwhile the world goes bumbling, rumbling on its precarious way: the Poles behaving very much like Poles, the Russians behaving very much like Russians, even the economy behaving very much like economies always do. It can all seem out of our control, and when it does, there must be someone to blame. Who? Why, of course, the Jews.

Anti-Semitism is for the simple-minded a final solution of any and every difficulty. If only it were only that. The bother is that it never stops there. It leads where it points and always in one direction. Not many steps beyond the mild anti-Semitic remark there is always torture and mutilation and death. Not only for the Jew.