President Clinton's whirlwind trip through Africa has been an unusually humbling experience for a American leader on the international stage.

During his 12-day trip, now half over, Clinton has repeatedly expressed contrition for past U.S. wrongs, including Cold War sup-port for despotic regimes, failure to recognize the extent of the 1994 Rwandan geno-cide, and American participation in slavery.And Friday, the president encountered the nearly unchallenged moral authority of South African President Nelson Mandela. The 79-year-old statesman chided Clinton over U.S. trade and foreign policy differences but nonetheless praised Clinton as a friend, supporter and key ally.

Mandela went unanswered by Clinton at a joint news conference when the South African leader staunchly defended close relations with Cuba, Libya and Iran on the grounds that they actively helped the struggle against the apartheid policies of South Africa's former white minority government.

Mandela then urged the United States to sit down and talk with its enemies.

"I have no doubt that the role of the United States as the world leader will be tremendously enhanced," he said.

But Mandela also stood up for his friend.

"There is one thing that you cannot be accused of - of not having the right instincts," Mandela told Clinton. "When we have differed on an issue, at the end of that, my respect for him is enhanced because I fully ac-cept his integrity."

Later, Mandela toasted Clinton at a state dinner, saying: "In you I have discerned an attachment to the aspirations of the most vulnerable sectors of society that comes from deep within your heart and soul."

Such endorsements from a man who has drawn the world's admiration for leading South Africa out of apartheid comes at a welcome time for Clinton, who at home in Washington is battling a major scandal over accusations of sexual impropriety and witness tampering.

White House aides breathed a sigh of relief when questions about the scandal failed to surface at the tightly controlled news conference, unlike a grueling session when British Prime Minister Tony Blair visited Wash-ington last month.

"No personal questions," quipped Man-dela near the end of the news conference, when a reporter addressed a question to him.

Clinton drew on Mandela's stature to describe his own visions of a moral, racially tolerant society.

After the two took an emotional tour of the Robben Island prison where Mandela spent 18 of 27 years in prison, Clinton said Mandela's example of overcoming adversity without bitterness was an inspiration.

"He is the world's foremost example of that," Clinton said. "Every young child I wish could think about his or her life that way, and there would be a lot more happiness in the world and a lot more generosity."