The Arab nations that have chosen to stand with Saudi Arabia and Kuwait against Iraq have cast off the chains of a meaningless myth that has held them in thrall for decades.

The confrontation with Iraq is not the end of Arab unity. It is the beginning of a meaningful Arab identity in world affairs. By declaring that they will go to war with Saddam Hussein if necessary -- as it may well be -- Egypt, Morocco and the others have changed history.

The action of these Arab nations can be in its own way as dramatic and consequential as Eastern Europe's breakout from the Soviet empire last year. Their decision also represents an attempt to escape a dying regional order as the world moves beyond the Cold War.

In the name of an Arab unity that existed only on the most superficial level, the modern Arab states have refused until now to recognize, and cut out, the moral cancer that has spread across their collective entity. They have refused to confront the evil that Saddam Hussein, Moammar Gadhafi and a few other Arab dictators have supported and have come to embody. Arab unity has meant a descent to the lowest common denominator for all Arabs.

The rape of Kuwait showed that the malignancy now threatens the entire Arab family. Saddam has forced his fellow Arab rulers to choose whether they will continue to mouth slogans or will act to protect themselves from a rabid creature loose in their midst. Those who resist him show that Saddam does not represent Arab values or Arab nationalism, that elusive concept being falsely invoked by some to condone Saddam's invasion.

Americans and Europeans have understandably focused on the importance of Middle Eastern oil fields to their economies. But the historical sweep of the conflict that Saddam has ignited is also vitally important. If the other Arab states, backed by the United States, do stop Saddam they will have begun to define a new, more hopeful nationalism in the Third World in the post-postwar era.

To accept Saddam as a legitimate figure of Arab nationalism is to misunderstand both Saddam and the nature of nationalism. Whatever support he stirs is based on frustration and hatred, on the politics of payback rather than of nationalism. His support is rooted in a fantasy of an otherwise idyllic Arab World despoiled by Western invaders who must be driven out and punished.

King Fahd of Saudi Arabia, Hosni Mubarak of Egypt and their allies have finally chosen to put this fantasy aside. George Bush has sent the 82nd Airborne to the Arabian Peninsula as much to encourage this political development as to protect real estate. Americans need to understand and support the political component of this mission.

Saddam, caught in the middle of a rape that he hoped would be quietly accepted, cries out that his crime is an act of Arab nationalism. Dispossessed Palestinians and Yemenis long exploited by the ''oil emirs'' respond with mindless enthusiasm to the destruction of the existing order by violence from any quarter. More surprising are Western commentators who accept Saddam's ex post facto pretense to be waging a nationalist uprising.

Saddam's political ''strength'' is built on a thirst for revenge by Arabs who blame the West for their vast problems and want payback. It is a ''strength'' that can create nothing. It can only destroy. Or be destroyed. That is the choice that Fahd, Mubarak and the others finally understood they confront.

The peoples of Asia, Africa and Latin America have long had reason to blame the United States and its European allies for many of their problems. The Cold War distorted American policies and aligned Washington against Third World nationalism in case after case. The need to expel first colonialist and then American influence and control became the driving force of nationalism for most in the Third World and many in the West.

The mythical force of Arab unity was fashioned out of the frustration Arabs felt over the post-World War I carving up of the region by Britain and France and the post-World War II creation of Israel in Arab-inhabited Palestine. The need to pretend that others were entirely responsible for their misfortune caused the Arabs to embrace a unity based on silence and on acquiescence to evil in their own ranks.

Saddam and his few Arab supporters say the Arabs must continue on this dead end. Those who oppose him show, at last, that there is another road. Those Arab states have acted out of immediate needs of survival. But they will also have thought about the tantalizing prospect that the Bush administration may successfully resolve the greatest challenge to stability in the Middle East since 1973 without having relied on Israel in any way.

Freed from the Cold War, the United States can also make a valuable contribution to a genuine Arab reawakening. The diplomatic skills George Bush has demonstrated in marshaling support at the United Nations and the muscle the 82nd Airborne brings to bear in the desert protect something more nebulous, but just as important, as oil wells.