On Jan. 15, 1983, President Reagan spoke in his radio broadcast of the need to "rededicate ourselves, young and old, black and white, to carry on the work of justice and totally reject the words and actions of hate embodied in groups like the Ku Klux Klan."

On April 16, 1984, the Ku Klux Klan, the hate-preaching vigilante group that terrorized rural black America for decades by murdering and lynching black people for the "crime" of being black, endorsed Reagan for reelection as president of the United States.

Unlike four years ago when the Klan endorsed the then GOP presidential nominee, Reagan has not repudiated this recent vote of confidence.

Why not, Mr. President? Have you changed your mind about blacks? Are you less sympathetic as the reelection campaign revs up into high gear? Could you (heaven forbid) even be looking for support from the Ku Klux Klan?

The refusal to reject the endorsement of one of the most notorious hate groups in America suggests that the Republicans are dallying in order to make maximum political use of the endorsement. But the issue at stake here is one of ethics, not of politics.

The Klan's endorsement of the president was ringing. "Anytime you see all the blacks and minorities in this country opposing, strongly, one man, you know he has got to be doing something good for the white race," said Imperial Wizard Bill Wilkinson, leader of the Invisible Empire, Knights of the KKK.

Then, before symbolically burning a 35-foot-high cross, he called some of the planks in the Republican Party platform "pure Klan" and continued: "They said we're opposed to affirmative action, we're opposed to forced busing and we're for states' rights. For those reasons we supported President Reagan and for those reasons we're going to support President Reagan this year. And God hope he will be elected this time."

The next day, when aides to the president were asked about this endorsement, they refused to comment.

The silence can't be excused on the grounds that Reagan is a busy man and doesn't have time to denounce every statement. He is surrounded by well-paid, quick-witted aides who are trained to pick up and respond to this sort of trouble. But far from seeing this as trouble, the president's men reacted in a way that seemed almost coy.

White House spokesman Larry Speakes referred questions to the reelection campaign. At reelection headquarters, spokesman John Buckley said, "We would not have any comment on it." The following day, Speakes, while saying that Reagan's views on the Klan had not changed in the past four years, still refused to repudiate the latest Klan endorsement.

When the Klan publicly backed Reagan in July, 1980, a time when the Nazis and the Ku Klux Klan were in resurgence, the then-GOP nominee quickly repudiated the sanction: "I have no tolerance whatsoever for what the Klan represents and will have nothing to do with anything of that kind," Reagan said. "Indeed, I resent their even using my name."

So why the delay this time? I can't imagine a Franklin Delano Roosevelt, whom Reagan has cited as a great president, allowing this endorsement hang in the air for an hour, let alone several days, without letting the nation know exactly where he stood.

This silence is even more upsetting in the wake of last week's outrageous acquittal by an all-white jury of six KKK members and three American Nazi Party members on charges of conspiring to disrupt a 1979 anti-Klan rally in Greensboro, N.C., where five demonstrators were killed.

Most Americans don't support the Klan. But for blacks, it conjures up images of violence and extreme danger. Many worry, too, about the subtle "Klan mentality" practiced by those who would never don a sheet but who are willing to let race or religion determine who should be treated like a first-class citizen. People of conscience have to denounce evil when it crosses their paths. The president's silence--and the apathy of good people--speak volumes. Blacks are expecting a white backlash against the record black voter registration. Is this the beginning? Is Reagan's silence a way to appeal to whites who are nervous about blacks finally, for the first time in their history, having a real impact on the presidential elections?

The bloody history of the Klan was given horrible, poetic reality by singer Billie Holiday in the song "Strange Fruit." I think President Reagan should kick these strange bedfellows out of his life or run the very real risk of being considered a hypocrite at best, a racist at worst.