WHEN THE IDEA of the "haves" and the "have-nots" first was clearly stated in the 1930s, the "haves" were the United States, France, and Britain, and the "have-nots" limited to Germany, Japan, and Italy. It was a decidedly European centered view, but, at the time, the political world was centered in Europe. Then came World War II and then decolonization.

By now, the "have-nots" of the 1930s have joined the "haves" of the 1970s, and the real split today is usually described in geographic terms, between and the North and the South, that is, between the developed and the developing nations - while the Soviet bloc rather stands aside.

According to what by now has become the conventional wisdom in both North and South, this split requires the construction of a new international order, one in which the new nations of the South will have much greater say. In the industrial democracies of the North, the dominant voice has become that of the "accommodationists," who clearly make such a case. Indeed, so strong has this widom become that some spokesmen for the Carter Administration will say that the "global issues" have become even more important than our relations with the Soviet Union.

Less articulate, for the most part, have been the "rejectionists," those who see no particular reason for the new order, and even less reason why we should rush to cooperate in constructing it.

Now there is a most effective rebuttal to the accommodationists, in the form of this slim volume by Robert W. Tucker, a political scientist at Johns Hopkins who has proved a skilled lacerater of conventional wisdom. Serveral years ago, he wrote an equally short book criticizing the Vietnam War on the very reasonable grounds that a much too expansive doctrine of national security was at the basis of the American involvement.

His new book, though dense and austere and uncompromising both in style and point of view, is one of the most important and penetrating contributions to the discussion about what should U.S. policy be toward the Third World. Indeed, it will do much to crystallize the issues in the debate.

Tucker's starting point is the character of international politics - that by nature, the international community is an anarchic world, in which the inequality and hierarchy of states is inevitable. States are not people living under a constitution that grants them equal rights. Rather, they are inherently different. Some have longer coastlines than others, some more oil, some more power.

The current international order, shaped and maintained to a considerable degree by the United States, is now under sustained attack.

But one of Tucker's most centtal points is that while the calls for a new order may be similar, the impulses in the First World and the Third World are very different.

The Third World countries are not arguing that the nation is not the basis of international politics. Indeed, they are emphasizing the role of the state. Their aim is to shift power themselves. This impulse Tucker labels the "new egalitarianism." There is nothing surprising in the fact that the Third World countries should seek greater power, for that is what nations usually seek.

More startling is the second category - what he calls a "new political sensibility" among liberal elites in the West. This sensibility - and the very word suggests an element of romanticism - is motivated, he argues, by a sense of guilt, an unhappiness with their own societies, and by a sense of shared humanity no less expansive than the once unchallenged doctrine of national security.

Tucker is not arguing that "shared humanity" should be denied. "What is novel," he says, "is the insistence that men now act upon this assumption in a manner they have not acted in the past, that they draw positive duties of distributive justice from it that they had not heretofore drawn, and that they give a scope to those duties they have never before been willing to give. The simple, though decisive, claim of the new political sensibility is that we no longer differentiate, for certain purposes, between fellow citizens and mankind."

This sensibility is Tucker's real target. He finds little real basis for the Westerners' sense of guilt toward the Third World, or for the assumption that Third World naitons can claim some special moral superiority. The sensibility is based, he writes, "upon a mistaken - at the very least, undemonstrated - view of what self-interest requres in today's world. It dies not require that the rich must make concessions to the poor because in a confrontation with the poor the rich are, by virture of their riches, vulnerable in a way the poor are not. The power of the poor that has been made so much of in recent years is either largely a piece of romantic nonsense or - more likely - a relfection of an underlying, if largely unexpressed, conviction that the patrimony of the developed and capitalist states is, after all, hardly worth defending - either because it was largely achieved through the exploitation of others . . . or because the affluence that has been created is itself a form of corruption."

Further, he suggests, this sensibility is based upon a second delusion, a mistaken belief that the state's power is being eroded. Rather the new egalitarians emphasize the key role of the state.

But these two points of view have converged to make heavy demands upon the Western world, and the inability or reluctance of the West to resist them eaves Tucker most gloomy. He foresees a new international order not more stable or just or humane, but even more unstable and dangerous, because there will be such a sharp disjunction between power and force.

This "rejectionist" case, so effectively expressed here, can obviously be critiicized in turn. Perhaps Tucker has overstated the challenge. Maybe the talk of a "new world order" is only a game, what is really involved is not much more than a tinkering with tariffs and stabilizing of export prices. Perhaps.

At a deeper level, a critic could say that Tucker is really rejecting the force of industrialization as it spreads around the world. After ail, once upon a time, Britain was the world's only industrial power. The difficulties encountered in trying to accommodate oterh emerging industrial powers, most clearly Germany, helped precipitate the two world wars. That analogy might suggest an accommodationist course.

But Tucker's basic quesiton cannot be evaded. Why? Why give away so readily the power? Will we be better off, or will the anarchic international world become even more unpleasantly anarchic?This deeply pressimistic book is aking those in the West to avoid the easy course of slogans and vast, vague appeals, and rather to think clearly about what we would do and for what purpose.