Washington ? Race has long been an important force in American standing in world opinion, for better and for worse. In issuing its rulings about affirmative action this week, the Supreme Court spoke not just to the nation but also to the world and offered a much-needed positive message about the state of American society.

What the world saw was an imperfect society continuing to wrestle in public with the demons of racism, as it has done throughout much of its history.

Many other socially heterogeneous nations refuse even to acknowledge that such problems exist. They sweep their minorities’ grievances under a rug of silence. Arabs in Europe, Uighurs in China, Berbers in Algeria and many others are the victims of this widespread practice.

The Supreme Court’s reasoned, fundamentally fair majority rulings in two affirmative action cases and the acceptance by U.S. institutions, politicians and citizens of the binding validity of those rulings even as they debate them should provide a useful contrast to the American rogue superpower image that public opinion polls show is so rampant abroad right now.

It should at least raise the question for critics of whether a nation that emphasizes the importance of fairness, openness and legality at home as the United States does could long sustain brutal power politics and armed force as its chief instruments of policy abroad. Could the United States, or any other great power, really be John Locke at home and Thomas Hobbes abroad for very long?

I think not. Governments ultimately behave toward the rest of the world as they behave toward their own citizens. That was why Saddam Hussein was a grave international danger, and why China’s government still has far to go before attaining international legitimacy.

That is why the Bush administration must not think that dictators who may be momentarily useful in the war on terrorism can be counted on to promote democracy and liberty in their region if given a little time and coaching. And finally, it is why George W. Bush has such limited opportunity to become world dictator (a goal often imputed to him abroad) when he and his government are under constant scrutiny and challenge at home.

Race is a particularly clear example of how this inside-outside continuum works. The horrors of slavery, the disgrace of segregation and more recently the moral and legal victories of the civil rights movement have had powerful roles in defining who Americans are to themselves and to the rest of the world.

In 1954, the Supreme Court ruled against school segregation and began changes in America that eventually deprived Soviet propagandists of a valuable Cold War weapon. The justices’ opinions this week in two affirmative action cases at the University of Michigan do not have that kind of dramatic effect, but they will, as the British newspaper The Guardian editorialized Tuesday, “shape the debate about social advancement not just in America, but around the planet.”

That is an appropriate and useful American role, even if the justices do not acknowledge the international dimension of their jurisprudence, which is expanding greatly in the era of globalization.

Justice Sandra Day O’Connor’s descriptions of the “compelling interest” that diversity holds for America should echo loudly in other societies where class, race, conspiracies of silence or brute force have been used to disadvantage entire categories of people and impoverish the nation of their talents. In today’s world, it is impossible to maintain national cohesion or economic competitiveness without diversity, as O’Connor’s unusually cogent and expansive opinion underlines.

It is even helpful in some ways internationally, though unfortunate, that the Bush administration did not in fact favor the outcome the justices reached. America is much more than the Bush administration, a fact that has been easy to forget overseas in the aftershocks of 9-11 and the war in Iraq.

More than any other single factor, it is the progress I have witnessed in America’s race relations in my lifetime that makes me optimistic about society’s ability to change under the rule of law and enlightened political leadership.

To be sure, an enormous amount remains to be accomplished in providing equal opportunity or, at a minimum, a sense of being treated fairly, to all U.S. citizens. But those goals are now widely and officially accepted as the American way. It is a struggle worth conducting, a struggle that is valuable even if success remains incomplete for the moment.

Jim Hoagland is a columnist for Washington Post Writers Group.