What is left to say about Stephen Walt and John Mearsheimer’s “The Israel Lobby and U.S. Policy,” published by Harvard’s John F. Kennedy School of Government, that has not been said? It’s a shoddy piece of pseudo-“scholarship” whose attack on Israel and American Jewish support for it, perfectly acceptable (although no less foolish) had it been expressed in a political opinion column, is a disgrace when dressed up as a piece of academic research. Just about everything it has been accused of being by its critics is correct, except perhaps for the charge of anti-Semitism, which is in all fairness exaggerated.

And yet there is one aspect of the Walt/Mearsheimer paper that has perhaps been insufficiently discussed. This is the question of what weight, in relating to the foreign policy of their government, U.S. citizens, Jewish and non-Jewish, should give to the two elements of what the paper’s authors refer to as “strategic interests” and “compelling moral imperatives.”

Messrs. Walt and Mearsheimer affirm that both “strategic interests” and “moral imperatives” are legitimate considerations in determining American foreign policy and then proceed to argue that neither of them justifies support for Israel. Their critics have done the reverse and argued that both do. Their case is the stronger one.

But what if one of these considerations justified it and one didn’t? Suppose that it really was not in America’s strategic interest to support Israel but that American Jews nevertheless felt morally impelled to do so. Would there be anything improper in their continuing to lobby on Israel’s behalf as vigorously as they do now?

This is not, after all, a purely theoretical question. Wherever one’s sympathies in the Israeli-Arab conflict may lie, even the most ardent backers of Israel, if honest about it, would have to concede that Israeli and American interests have at times clashed in the past and will at times clash in the future. Is it “disloyal” of American Jews when this happens to take Israel’s side against America’s?

One’s first, instinctive answer might be, “Of course it is.” Shouldn’t an American citizen always prefer the interests of his own country first?

But that’s a misleading instinct. Let’s forget about Israel for a minute. Let’s take another case. Darfur, for example.

No sane person would dispute that hundreds of thousands of black Africans have been murdered in western Sudan in recent years by a genocidal Arab government in Khartoum. Still, there is quite clearly no “strategic interest” of any kind that would seem to call for American intervention in Darfur – which is, presumably, why the U.S. government has shown no inclination to intervene. Why spend large sums of American money, commit American troops, and lose American lives, while at the same time antagonizing Arab governments, in order to protect the population of a godforsaken region of Africa whose only natural resources are drought, misery, war and death?

And so the people of Darfur will go on dying.

Suppose, though, that there were in the United States – as there is not – a powerful Afro-American lobby that cared about the people of Africa. Suppose this lobby used its great political strength to pressure the American government into sending troops to Sudan. Suppose that these troops were actually sent and succeeded in putting an end to the slaughter against the protests of the Arab world. Would Stephen Walt and John Mearsheimer then write another paper castigating the “black lobby” for sabotaging American foreign policy?

Perhaps they wouldn’t. Perhaps they would say that this is a case in which “moral imperatives” outweighed “strategic interests.” And no doubt they would also say that it differs from the case of Israel, which is not a victim like the blacks of Sudan, but itself a victimizer.

But moral imperatives are in the eyes of the beholder. Where Messrs. Walt and Mearsheimer see only a cruel colonizer-state oppressing poor Palestinians, most American Jews see a brave little country of a long-exiled people, their people, returned to its land – a people that one set of genocidal maniacs almost annihilated half-a-century ago and that another set, which is an ally of the same poor Palestinians and is within striking distance of acquiring nuclear weapons, is now threatening to annihilate again.

There is no point in arguing whose image of Israel is closer to the truth, that of Stephen Walt and John Mearsheimer or that of American Jews, just as there would be no point in arguing with a spokesman for the Arab League whether the inhabitants of Darfur are blameless targets of savagery or cunning rebels who deserve their fate. To each his own version. But if my version tells me that I am faced with a moral imperative, that is the version I am required to act on.

An “all-powerful” Israel lobby? Would that there were more like it! Would that there had been an all-powerful Cambodian lobby in 1973, and an all-powerful Bosnian lobby in 1993, and an all-powerful Rwandan lobby in 1995! Would that there were an all-powerful Darfur lobby today! Would that other Americans would learn from American Jews that their country’s strategic interests are not everything and that there are sometimes other things that matter more!

America’s standing by Israel over the years is one of the things that its foreign policy makers can feel proudest of, just as America’s doing little or nothing to prevent the murder of legions of Cambodians, Bosnians, Rwandans, and Sudanese is one of the things to feel most ashamed of. That America has that much reason for pride is something that, in large measure, it can thank the Jewish lobby for.

Mr. Halkin is a contributing editor of The New York Sun.