After many months of testing the waters, of once having filed papers and then having withdrawn them, City Councilman David Clarke has announced that he will not run for chairman of the D.C. City Council. Clarke deemed himself ineligible by reasons of birth: He is white.

Clarke went further than that. He suggested that Ronald Reagan has so poisoned the atmosphere that no white should now take on a black incumbent. In response, heads all over town seemed to nod in agreement. From the political leadership has come not a whimper of disagreement. There have been no ringing oaths to the idea that a candidate's race should be irrelevant. The story made the paper one day and was gone the next. It now lies, presumably, on the bottom of countless bird cages.

What the Clarke Manifesto means for the mayoralty candidacy of Betty Ann Kane remains to be seen. She is white, and Mayor Marion Barry is black, and according to Clarke's reasoning, only Kane among the eight mayoralty candidates should not be running. Like Clarke, she was fatally afflicted at birth. Goodbye Kane.

And goodbye, too, any notion that a candidate should be judged on experience, abilities, ideas--anything, in fact, but race. To Clarke, and to a whole lot of people whose silence is deafening, the most important criterion appears to be race. A white should run only when there is no black incumbent. Otherwise, no matter how good a white candidate might be, no matter how experienced, bright, brilliant, clean, reverent and healthy, he or she has no business in the race.

It goes without saying, of course, that race can be important. The majority of Washingtonians, who are black, long were governed by a minority in whose behalf Jim Crow laws were implemented and administered. Washington once had a segregated school system, lunch counters, park system and the rest. In spirit and in law, it was in many ways just another Southern town and the memory of those days has not yet faded.

It's hard to be critical of Clarke who at least was being candid. And while there may be some reason to question both his polling data and the reason for his statement, he is not the only one to either discover or sense a widening racial split in this city. What he reports is something of a dismal consensus.

It's not hard, though, to be critical of a political establishment that, judging from its silence, either accepts this racial gulf or welcomes it. It either has such a low opinion of Clarke that it dismisses what he says out of hand, or--more likely--it simply found nothing new in what he said. Washington has become a very cynical place. Clarke said something that is either shocking or tragic--and got nothing but a yawn for his efforts.

Clarke, after all, is not just any white politician. He was a civil rights activist--counsel for the Southern Christian Leadership Conference. And the ward he has represented on the city council, Ward 1, was mostly black when it elected him in 1974. More than most white politicians, he was in a position to prove that race can be irrelevant.

At least he should have given the voters that chance. It might be, as he has said, that racial divisions are worsening, that the Reagan administration has set back race relations a decade or two, but Clarke was in a position to show that Reagan is not all white men--just one white man, and not a representative one at that. Politicians should not merely read the poll data and throw up their hands. They have some obligation to try to change things.

It's disheartening that Clarke, a good man and a conscientious City Council member, did not try that. And it's unfortunate that his views, if accepted and implemented, will deprive the city of potential leadership. But, worse, his statement not only takes for granted, but accepts, what has to be called black racism. After all, Clarke is saying that blacks will vote against a candidate simply because he or she is white.

But Clarke's own career proves the opposite. Blacks, like other voters, are fully capable of seeing past a candidate's race. Black voters have done this with Dave Clarke before and they will probably do it again. He, not to mention the city's other politicians, ought to do them the the courtesy of seeing them the way they have seen him.