A smile that lightens up every room he enters, a great sense of humour and the capacity to put people at ease are part of Nelson Mandela's extraordinary ability to win people over.

Margaret Thatcher famously said "anyone who thinks the ANC will form the government of South Africa is living in cloud cuckoo-land." If Mrs. Thatcher may be faulted for lack of foresight, what to say of the U.S. State Department, which until recently had the ANC, South Africa's ruling party since 1994, on its list of terrorist organisations, whose members, including Nelson Mandela, needed a special waiver to enter the United States? Lack of hindsight?

This would be, I suppose, just another expression of what Richard Hofstadter called "the paranoid style in American politics." It has led to the imposition of such absurd rules as those that allowed, a few weeks ago, a Canadian airport security guard to confiscate the mother's milk of a returning-home, young American lawyer, who had laboriously pumped it from her breasts for her infant child back in San Diego, as it exceeded the prescribed limit (100 ml) of liquid airplane passengers are allowed to take on board.

Yet, outside the corridors of power of London and Washington (and even within some of them) Nelson Mandela, "Madiba" to his friends, is regarded as one of the very few iconic leaders of the twentieth century - up there with Franklin Delano Roosevelt, Winston Churchill, Mahatma Gandhi, Charles de Gaulle and Ernesto "Che" Guevara. As he turns 90, happily married to Graca Machel (the only woman to have been First Lady of two countries), he is still active, leading three foundations, collecting honorary degrees from 50 of the world's leading universities, and dividing his time between his native hamlet of Qunu in the Transkei and Johannesburg. The recent concert held in his honour in London, broadcast around the world 20 years after the one held in 1988 to demand his release, shows the enormous esteem he is held in.

I first met Nelson Mandela on a rainy, late June 1994 morning in De Tuynhuys, the South African President's office in Cape Town, when I presented my letters of credence. It was the first such ceremony for both of us, the 18th century building next to Parliament - which once housed the Governors of the Cape - was being refurbished (this was a scarce six weeks after Mandela's inauguration) and it took us a while to get going. Yet, after the speeches and the photo-ops, I had my 15 (that turned into 30) minutes in private with him and a couple of aides - that sound tradition that has fallen by the wayside in so many countries.

The standard template for such meetings is to exchange social pleasantries, and perhaps talk about the weather, but certainly not about any bilateral issues, about which the head of state would not necessarily be fully briefed. I departed from the script, took my chances and brought up the question of the potential creation of a Truth and Reconciliation Commission (TRC) in South Africa. Justice Minister Dullah Omar, a good friend, had been pushing for it, partly inspired by the Chilean experience with a TRC, but these were early days and there was no consensus either in the government or in the ANC. Mandela listened intently to my description of Chile's TRC, why it was considered to have set the standard for such bodies at the time, and why it represented a good compromise between two extreme solutions that had not worked to deal with an evil past: the creation of special courts to prosecute human rights violations under authoritarian rule, and, on the other hand, a blanket amnesty for those involved in such shenanigans.

I could see his mind at work, assessing what was at stake. Instead of asking one of his aides to take notes for a possible follow-up (that might never take place), which would have been the SOP for such a demarche, he asked me a couple of questions about how TRCs worked, and then whether I had anything in writing about the Chilean Commission. I happened to have an 80-page, English-language summary version of the three-volume report of the latter, which I sent to him by hand that very afternoon.

I would like to think that exchange played a role, however small, in the subsequent launch of the South African TRC, whose activities became one of the defining features of Mr. Mandela's presidency, and a body that, under the leadership of Archbishop Desmond Tutu and his deputy, Alex Boraine, would set a new standard for Truth Commissions. In 1998, when the South African TRC delivered its report, including criticisms of what had transpired in the ANC camps, the party made a big ruckus, but Mr. Mandela held his peace.

In this, as in so many other matters, Mr. Mandela showed an uncanny sense of that "middle road" that marked his presidency and his leadership - one that stood for certain basic principles, without necessarily antagonising and alienating his adversaries and political rivals. One year after our initial meeting, in June 1995, his famous gesture of donning the South African rugby team's captain's jersey (a sport widely identified with whites and white supremacy) in Johannesburg's Ellis Park Stadium, on the day the Springboks won the Rugby World Cup, was emblematic of his push for reconciliation, and did much to bring Afrikaners around to the country's new dispensation.

Less known is his visit to Betsy Verwoerd, the widow of former Prime Minister Hendrik Verwoerd, the true architect of apartheid. In late 1994, Mr. Mandela hosted a lunch party in Johannesburg for prominent South African women from all walks of life: Adelaide Tambo, Amina Cachalia, Nadine Gordimer, Helen Suzman and Frene Ginwala were all there. He invited Betsy Verwoerd, who lived in Orania, a town in the middle of the Orange Free State (originally set up, in the Afrikaner delirium, as a "whites only" town) but she declined. Shortly thereafter, Mr. Mandela flew to Orania and had tea and koeksusters with her, thus reaching out to Afrikaners in the very heart of their laager.

After being imprisoned and "banned" (meaning he became a "non-person", who could not be quoted or mentioned in the media or in public) by the apartheid regime for 27 years, Mr. Mandela suddenly found himself surrounded and idolised by white, Afrikaner children during his visits to schools, something to which his regal bearing and innate elegance helped - to see him with Queen Elizabeth during her 10-day visit to South Africa was to see two monarchs, one a democratic one, the other a constitutional one, with great respect and appreciation for each other.

Mr. Mandela's ultimate leadership act was his decision, announced early in his presidency, not to stand for re-election, thus depersonalising and institutionalising South Africa's democratic transition, giving it a stability so sadly missing in so many other African countries (witness Zimbabwe today), where the penchant of leaders to perpetuate themselves in power, even long after their welcome period has expired, has caused so much harm. Much as Turkey's Kemal Ataturk provided the role model for the effective reformer in 20th century politics, Mr. Mandela has provided the one for the democratising leader that successfully makes the transition from head of the liberation struggle to advocate for peaceful reconciliation, something very few of his counterparts have managed anywhere.

Mr. Mandela's significance and success, then, goes way beyond that much overused word - charisma, though he has plenty of it. A smile that lightens up every room he enters, a great sense of humour (whenever he would meet us he would ask my wife, "do you remember me?") and a remarkable capacity to put people at ease are part of this extraordinary ability to win people over, be they friend or foe. His loyalty to those who supported him and his struggle is legendary. Taiwan kept its Embassy in Pretoria till 1997, as he refused - against the opinion of many advisers - to break diplomatic ties with Taipei. He also publicly expressed his gratitude to Indonesian strongman Suharto, not exactly a champion of democracy, by inviting him for a state visit to South Africa.

So has been his ability to change course as the political situation demanded. In the 60s, as the apartheid state swung into full repression mode, he moved from non-violent, Gandhian opposition to white rule to espousing armed struggle. And then, in the 90s, he switched back again from armed resistance to peaceful negotiation and reconciliation - but only after being released from prison, pointedly refusing an early 1985 release entailing a commitment to giving up the struggle, arguing that " only free men can negotiate; prisoners cannot enter into contracts."

Happy birthday, Mr. President!

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