President Clinton and South African President Nelson Mandela strolled arm-in-arm today through the island prison where Mandela was held for 18 years, the emotional peak of a day which the world's most powerful leader spent by the side of the leader viewed by many as the most respected.

All day long, two starkly different presidential styles were on display. At a news conference in the garden of Cape Town's presidential residence, Clinton wore a dark blue suit, and Mandela wore a loose-fitting, brightly colored floral African shirt. Mandela, 79, had some difficulty negotiating the steps leading to the sunny garden where their conference was held, but Clinton, nearly three decades his junior, was at his arm to help.

Mandela, who rose to power by standing up against a brutally repressive, white-minority regime, was gracious but also as blunt-spoken a foreign leader as has ever been in Clinton's presence. He prominently mentioned his good relations with Libya and Cuba, both subjects over which he and the United States are at odds. Clinton, who rose to power by charming voters, was smooth-spoken and deferential, playing down disagreements with his host over trade.

But the 42-minute exchange also showed two politicians, each with a common interest in using the other's stature to enhance his own.

Mandela plainly basked in his younger guest's power. Hosting the leader of "the greatest country in the world," Mandela told reporters, is "the high-water mark" in a long stream of foreign leaders who have come here to pay tribute to the new, post-apartheid South Africa.

And Clinton just as plainly basked in the aura of moral authority that has made Mandela so revered. The South African's journey from political prisoner under apartheid to president of this country's first true democracy, Clinton said, is a lesson "in how fundamental goodness and courage and largeness of spirit can prevail over power lust, division and obsessive smallness in politics."

While that reference seemed to refer to certain controversies that have beleaguered Clinton back home, he never mentioned them. And, strikingly, neither did anyone else. The president, aides said, had braced himself for scandal questions, but the subjects of Monica Lewinsky or Kenneth Starr or executive privilege or fund-raising simply never came up -- the first time in two months that has happened in any extended exchange between Clinton and journalists.

It was as if the luminescent presence of Mandela -- who at one point said of Clinton, "I fully accept his integrity and bona fides" -- had briefly chased away the usual appetite for controversy.

Later in the day, Mandela played host to Clinton at a state dinner in the spectacular mountain vineyards that lie about an hour's drive from Cape Town at Verlegen, a 17th-century estate. Clinton was awarded South Africa's Order of Good Hope -- an honor that has also recently been accorded Libya's Moammar Gadhafi.

Mandela's relationship with Gadhafi has been perhaps the most prominent irritant in the U.S.-South African relationship. Libya is harboring suspects in the bombing of the Pan Am jetliner that exploded over Lockerbie, Scotland, in 1988, refusing to release them for trial.

But Mandela made no effort to play down his warm feelings for Libya. Instead, he brought it up in the opening statement of the news conference. He mentioned as well the state visit he hosted for Cuba's Fidel Castro, another outcast in U.S. eyes.

"I do that because our moral authority dictates that we should not abandon those who helped us in the darkest history of this country," he said. "Not only did they support us in rhetoric, they gave us the resources for us to conduct the struggle, and the will."

Mandela, who will not seek reelection when his term expires next year, seemed to urge the United States to be more open to its enemies. Noting that his African National Congress works with the whites who banned the party and repressed the country's black majority, Mandela said, "It was very repugnant to think that we could sit down and talk with these people, but we had to subject our blood to our brains."

And he offered some blunt advice to his domestic critics: "Those South Africans who have berated me for being loyal to our friends -- literally, they can go and throw themselves into a pool."

That remark left Clinton laughing. But Mandela said he meant no disrespect for Clinton in his embrace of Cuba and Libya, as well as Iran. To the contrary, he praised both Clinton and first lady Hillary Rodham Clinton as having "correct instincts on the major international questions facing the world today." For his part, Clinton never addressed the foreign policy disputes. Instead, he labored to soothe South African fears about various topics, including an administration-backed trade bill pending in Congress that many Africans say will hurt their nations by leading to a cut in foreign aid. "Increasing trade does not mean decreasing aid," Clinton said, adding that African nations will be helped by greater access to the U.S. market as long as they make progress on human rights and expanding democracy.

For the most part, Clinton's day was devoted to celebrating Mandela's example.

On Robben Island, where offshore winds kicked up choking clouds of dust, the two leaders visited the six-by-six-foot Cell No. 5 that was Mandela's home and the quarry where he and other prisoners toiled.

"You know, 99.9999 percent of the people will never have a challenge like the one Mr. Mandela faced when he spent all those years in prison," Clinton told reporters. "But everyone has difficulties, everyone faces unfairness, everyone faces cruelty. And the one thing that is beyond the control of anyone else is how you react to it, what happens to your own spirit, what happens to your own heart, what happens to your own outlook on life." CAPTION: On Robben Island, Presidents Mandela and Clinton walk toward Cell No. 5, where Mandela was long imprisoned. Clinton praised his host's "fundamental goodness and courage and largeness of spirit," while Mandela said the U.S. leader's visit is a "high-water mark."