The original question had to be edited. I would suggest that what makes Mandela such a great leader is his willingness to sacrifice for a larger cause. Mandela is inspirational because he never wavered in making the ultimate of sacrifices in the cause of eliminating Apartheid. Mandela could have taken a path of less resistance, optioning for a practical solution that would have served his self- interest. Yet, he did not. He accepted that which is more difficult to demonstrate his unwavering commitment for a cause larger than himself.
Speaking in his defense in his 1964 trial, Mandela's words showcase his greatness as a leader. The speech shows how he never relents in his beliefs. The opening words of "I am the first accused" sets the tone for the notions of sacrifice, commitment, and demand of justice that suggests his greatness as a leader:
At the outset, I want to say that the suggestion made by the State in its opening that the struggle in South Africa is under the influence of foreigners or communists is wholly incorrect. I have done whatever I did, both as an individual and as a leader of my people, because of my experience in South Africa and my own proudly felt African background, and not because of what any outsider might have said.
Mandela understands his role as a leader. He clearly recognizes that he has an obligation and these words show how he will not waver in honoring it. Later in the speech, when Mandela states "I can only say that I felt morally obliged to do what I did," it speaks to an ethical sense of courage that underscores his greatness as a leader. Mandel's words remind us that leadership, truly virtuous stewardship, is not derived from political calculation or focus groups that test out a message. It comes from the intestinal fortitude to stand for an ideal that preserves the fabric of something larger than the individual.