Obama recalled the words Mandela spoke in the dock at his 1964 trial on charges of plotting to overthrow South Africa's apartheid government: "I have fought against white domination, and I have fought against black domination. I have cherished the ideal of a democratic and free society in which all persons live together in harmony and with equal opportunities. It is an ideal which I hope to live for and to achieve. But if needs be, it is an ideal for which I am prepared to die."
Obama called Mandela "one of the most influential, courageous, and profoundly good human beings that any of us will share time with on this Earth. He no longer belongs to us -- he belongs to the ages."
"I am one of the countless millions who drew inspiration from Nelson Mandela's life," Obama said. "My very first political action, the first thing I ever did that involved an issue or a policy or politics, was a protest against apartheid."
Former U.S. President Bill Clinton said in a statement Mandela was one of history's "most important leaders and one of its finest human beings."
"History will remember Nelson Mandela as a champion for human dignity and freedom, for peace and reconciliation," Clinton said. "We will remember him as a man of uncommon grace and compassion, for whom abandoning bitterness and embracing adversaries was not just a political strategy but a way of life."
Former President George W. Bush, in a statement, said Mandela "was one of the great forces for freedom and equality of our time. He bore his burdens with dignity and grace, and our world is better off because of his example. This good man will be missed, but his contributions will live on forever."
Archbishop Desmond Tutu of South Africa -- like Mandela a Nobel Peace Prize winner for his work on overturning the nation's apartheid government -- wrote in an op-ed for allafrica.com Mandela "will go down in history as South Africa's George Washington, a person who within a single five-year presidency became the principal icon of both liberation and reconciliation, loved by those of all political persuasions as the founder of modern, democratic South Africa."
Anti-Defamation League National Director Abraham Foxman said Mandela "will be long remembered as one of the greatest figures of his generation and one of the most inspirational and effective freedom-fighting figures in modern history. In a world where the word "hero" is too readily bandied about, Nelson Mandela was a true hero of freedom who brought historic change, and did so peacefully."
The Council on American-Islamic Relations in Washington called Mandela's death "a loss for all humanity."
"His legacy of uncompromising perseverance in the face of bigotry and injustice will live on for generations to come," said CAIR National Executive Director Nihad Awad.