Something extraordinary happened a couple of weeks ago. A group of distinguished black Americans called for sanctions against an African leader.

I'm not talking about pro-forma tongue-clucking of the sort that was directed against Uganda's Idi Amin toward the end of his regime or the careful statements calculated to establish a record of opposing brutishness without offending anyone.

I'm talking about a strongly worded statement urging both the administration and Congress to suspend all military and economic assistance to the government of Kenya's Daniel arap Moi.

"The African-American community has cried out for democracy and justice in South Africa and urged an end to the bloodshed caused by white oppressors," said Randall Robinson, executive director of the pro-Africa lobby TransAfrica, in releasing a letter that had been sent to President Bush. "We must also stand together to call for an end to the violence and tyranny caused by black oppressors in Kenya."

The letter was signed by some of the most respected black leaders in the nation: Robinson, Jesse Jackson, Coretta Scott King, Rep. Ronald Dellums (D-Calif.), New York Mayor David Dinkins, former Gary, Ind., mayor Richard Hatcher, Dorothy Height of the National Council of Negro Women, Ben Hooks of the NAACP, Joseph Lowery of the Southern Christian Leadership Conference and William Lucy of the Association of Federal, State, County and Municipal Employees.

The surprise is not that these men and women are outraged at Moi's brutal tyranny. Black American leaders have often been outraged at the excesses of African leaders -- at least privately. The surprise is in the letter's forthright call for tough sanctions to force Moi to release all political prisoners, guarantee human rights, end harassment of the press and move away from the single-party politics that have been the hallmark of countless African regimes.

"U.S. taxpayers' money must not be used to supply arms and funds to a government that stifles freedom of expression with violence and protects its own power through repression," the letter said.

Signatories will insist that this is not the first time they have spoken out against black tyranny, and it is true. Some of them spoke out against Amin and Ethiopia's brutal Haile Mariam Mengistu. Others have criticized Zaire's Sese Seko Mobutu, Liberia's Samuel K. Doe and various other tyrants in Africa and the Caribbean. But the criticisms have usually been piecemeal, muted and careful, often balanced with blame directed at the governments of American and Europe.

What occasioned the new attitude?

Part of the explanation may be the presence here of Gibson Kamau Kuria, the human rights lawyer who had recently been forced to flee his native Kenya and who attended the press conference. But a larger part, I suspect, is a growing maturity among black American leaders who -- at least in international affairs -- see the value of measuring justice by a single yardstick.

It still hasn't happened domestically. Black American politicians who run afoul of ethics or the law can still count on either silence or mild rebuke. For instance, Ben Hooks, speaking at the recent convention of the NAACP, could not find the words to condemn the behavior of D.C. Mayor Marion Barry, who has admitted to using cocaine and who has lied about it.

He called on black Americans to take responsibility for their own lives and to declare "a moratorium on excuses." But he diluted his message with talk about unspecified "convenient and selective prosecution of black leaders."

There is in black America an understandable reluctance to condemn black leadership, no matter how deserving of condemnation. It is almost always easier to mount a defense fund for a black official charged with criminal activity than to generate a statement condemning the behavior. It's painful to say things that can be used by our enemies.

But leadership entails a willingness to endure a certain amount of pain in the interest of truth. And by that measure, we've had too little leadership.

That may be changing. A number of black Washington leaders are starting to find the courage to say that the voices that seek to shift the blame for Barry's behavior from Barry himself to "overzealous" prosecutors are not the only voices in town. Black people, they are saying, must set their own standards of acceptable behavior.

That is the significance of the TransAfrica statement on Moi. Randall Robinson understands as well as anyone the legacy of African colonialism and exploitation. But he also knows a tyrant when he sees one -- even if that tyrant wears a black face.

The crucial question is finally on the table: If we insist that whites have no standing to set standards for the behavior of black officials while refusing to set the standards ourselves, by whom will the standards be set?