Nelson Mandela loomed large for each of the four US presidents who honoured him yesterday - as a distant mentor, a personal counsellor, a wartime critic and a fellow world sage. President Barack Obama and predecessor George W. Bush flew together aboard Air Force One to South Africa for the memorial service. Two other former presidents, Bill Clinton and Jimmy Carter, made their own way there. Watch: Mandela: from US 'terrorist' to hero Obama has long revered Mandela as the political idol who drew him into politics. As a 19-year-old student in California, the young Obama happened to hear two African National Congress envoys speak of the trials of Mandela and the anti-apartheid struggle. Inspired, Obama adopted the cause and gave the first, halting speech of a career that would eventually make its own racial history. "As I look at that 19-year old young man, I'm more forgiving of the fact that the speech might not have been that great," Obama said in Cape Town during a visit in June. "Because I know now that something inside me was stirring at that time, something important. And that was the belief that I could be part of something bigger than myself, that my own salvation was bound up with those of others." While Obama's emotional and political connection with Mandela is deep, he knew his hero only from a distance. They met briefly when Obama was a newly minted senator in 2005 in Washington and spoke several times by telephone. But the long-awaited public meeting of the first black presidents of South Africa and the United States never happened. Obama judged Mandela too sick to visit when he was in South Africa earlier this year. I realised that they could take everything from me, but my mind and my heart MANDELA ON TIME IN PRISON If Mandela was a mentor to Obama, he was a friend to Clinton, who was in office for the entirety of the prisoner-turned-president's 1994-1999 rule. As he endured a public ritual of repentance after the scandal over his affair with White House intern Monica Lewinsky, Clinton revealed in 1998 how Mandela had helped him deal with his demons and his enemies. "He said, 'I realised one day, breaking rocks, that they could take everything away from me - everything - but my mind and my heart. Now those things I would have to give away, and I simply decided I would not give them away,'" Clinton said, relating a conversation with Mandela. Clinton said those words helped slake his own fury at the Republicans who impeached him. By the time Bush became president Mandela was retired. But he criticised Bush over the pending Iraq war in 2003. "What I am condemning is that one power, with a president who has no foresight, who cannot think properly, is now wanting to plunge the world into a Holocaust," Mandela said. In 2005, Bush welcomed Mandela to the Oval Office for a visit. Mandela offered gratitude for the US leader's multibillion-dollar HIV/Aids fight in Africa, but did not withdraw his remarks on Iraq. Mandela was in jail for the entirety of Carter's presidency. But he came to know Mandela as a fellow ex-statesman. Carter attended the memorial events alongside other members of "The Elders" group, Desmond Tutu, Henry Kissinger and Kofi Anan. The group of former world statesmen was founded by Mandela.