RONALD REAGAN, the man who proclaimed:

"The Civil Rights Acts are bad legislation."

"The welfare bureaucracy . . . is riddled with waste and fraud."

"Affirmative action is a bureaucratic witch hunt."

The man whose platform was glowingly endorsed by the Ku Klux Klan. There would seem to be no reason on earth why blacks would heed his clarion call or even give him the time of day.

But this past week in New York, the aging conservative Republican came before the 70th annual convention of the largely black and largely Democratic National Urban League, and from the moment he bounded upon the platform, surprisingly, people listened.

Not only did people listen, but some interrupted his speech with applause, others stood and clapped when he finished and he scored a few points with his pitch for more jobs.

Clearly, many were unmoved, and Reagan was later shouted down in South Bronx. But the reception given candidate Reagan on his maiden voyage into the black community was no fluke. It seems to at least suggest deepening frustration among blacks with the Carter administration. And while it is unlikely that Reagan will make serious inroads into the black vote come November, clearly, Jimmy Carter cannot take the black vote for granted this time around.

The blacks at the convention listened because they were curious, and because it was novel for such an audience to be so blatantly wooed by a Republican (and a conservative one at that).

They listened because leaders like the Rev. Jesse Jackson had been openly flirting with the GOP, hoping to stimulate competition for the black vote. Maudine R. Cooper, the Urban League's vice president for Washington operations, echoed Jackson's line at the convention, saying, "We cannot be wed to any party or candidate."

And they listened because they see the lines between the GOP rightists and the prevailing Democratic conservatives blurring as never before.

Reagan does not have to win the black vote -- as Jimmy Carter did in 1976 -- in order to capture the White House. He couldn't win that vote anyway. Reagan's strategy is basically a negative one: to avoid arousing black to vote against him, to neuatralize the black vote.

"He intends to shave off some blacks votes with appeals to jobs, black business ownership and black colleges," says Jackson, "and paralyze some other black votes by raising up some of the unfulfilled commitments of the president." Reagan is counting on black apathy to make the margin of difference.

To help accomplish these ends, Reagan left the sedate setting of the New York Hilton after his speech, made the obligatory visit to the debris-strewn South Bronx, traveled to a black publishing company in Chicago and dropped by Jackson's Operation PUSH headquarters -- all in the same day. He got in so deep, one black advance man felt obliged to warn him he had other constituents.

It was a good show.

But then Reagan is an actor, and is given to proffering tiny solutions to large problems, and he brought his tunnel vision to the League in a smoothly delivered address that suggested few substantive programs.

In face, the speech was notable more for what it did not say than for what it did say. He didn't mention racism as a leading barrier to black opportunity. He didn't mention public education. He didn't talk about affirmative action. h

He did obliquely praise "states rights" -- a euphemism for removing minimum federal standards and protections that always spells repression for minorities and the poor.

Some quickly recognized that the show was just that. As John W. Mack of the Los Angeles Urban League grumbled afterward: "It's fine to focus on jobs, but blacks should not become so caught up in economic development that we have a few black millionaires and the rest are still starving and suffering. . . .

Despite the many shortcomings, there may be a Reagan factor in the black community this fall. Disenchantment with Carter runs deep. The jury is still out on Reagan, his repudiation of the Klan's endorsement notwithstanding. But no one at the League convention was willing to tell Reagan where to go. And that's quite different than many would expect.