ONE semester, about 10 years from now, the Kennedy School will undoubtedly offer a seminar on the problems of urban race relations in the 1980s--and the summer of 1989 in New York City could easily be used as the definitive case study.

This past summer is likely to go down in history as the time when racial tensions--or, at least, the perception of racial tensions--reached its peak and threatened to divide a city already split among many economic, social and ethnic groups.

But amid the cries of outrage, the threats of revenge and half-hearted attempts at racial reconciliation, this summer may also have seen incidents that will cause the current wave of racial tensions to buckle under the weight of its own irrationality.

THE agenda for the summer of '89 seemed to be set early, as New Yorkers were introduced to the Spike Lee doctrine via his most recent film venture, Do the Right Thing. Reactions to the film ranged from the intellectual to the hysterical:

The movie will make the Blacks riot, caller after maniacal caller preached on inane AM radio talk shows. No, the movie is merely weighing the morality of King's doctrine of non-violence and Malcolm X's acceptance of violent options, argued Upper West Side liberals.

What did the movie actually do? Exactly what Spike Lee, in countless interviews, has said he wanted it to do--it made people think. New York's attention was now focused on the state of racial relations in the city, but the focus sometimes clouded the heart of the issue and exaggerated its most sensational effects.

So when a Black youth was killed allegedly by a gang of white teenagers in the predominantly white Bensonhurst section of Brooklyn, everyone was shocked, but no one seemed really surprised.

A media market rife with three tabloid newspapers and half-a-dozen trashy local television news shows gobbled up the appalling incident and gave New York what they thought it wanted to see--the final showdown in a racial turf war that nobody could win, while ignoring the very real underlying problems which the incident represented.

The Bensonhurst killing was the catalyst for a series of demonstrations which provided more sensationalist material: some Black leaders marched through Bensonhurst and a handful of white Brooklynites shouted racial epithets at them. Several days later, thousands of demonstrators marched through Brooklyn and eventually clashed with police when they were not allowed to cross the Brooklyn Bridge.

IN the midst of the August insanity, Mayor Edward Koch was standing on his last political legs, fighting off a serious primary challenge by David Dinkins, who is Black. Not surprisingly, the two candidates stayed clear of blatant racial appeals--such tactics are tantamount to political suicide in light of New York's diverse electorate.

But the election became almost a referendum on the future of race relations in New York City. Although Koch was trying to win back the Black electorate (which he deperately needed to do), his tone was typically shrill and aggravating.

So when soft-spoken Dinkins made the appeal for a unified New York a cornerstone of his campaign, the election fell right into his hands. Dinkins did not represent the radical and highly vocal minority of New Yorkers who wanted to avenge the Bensonhurst murder.

Instead, Dinkins appealed to the rational majority of New Yorkers--those who knew that, despite the mood of hysteria that had engulfed the city with the hot and humid summer air, a majority of New Yorkers of different races actually wanted to get along.

This was the opinion expressed to me at David Dinkins' victory party last week by one of his key campaign workers. He went on about the beautiful mosaic of races which Dinkins represents and about how New York will be reunited once again.

When I finished speaking to him, he took my white hand with his Black hand and held it up in the air. "This is what New York is about, man," he said. "Together."