The mark of a great leader is being prepared to tell your people what they don't want to hear.
It's being ready to stand up for what you believe is right, even when this entails overruling cautious advisers, or ignoring discouraging opinion polls.
A great leader knows that vindication may not come immediately, that received wisdom can move slowly (sometimes too slowly, in a democracy, to secure re-election).
But in the long run, we can see who stands on the right side of history, and who does not.
Nelson Mandela and FW de Klerk, each former South African presidents, fit into the former category.
Both men have flawed records, (yes, even Mandela) but at a crucial time they had the courage and wisdom to steer South Africa away from the abyss.
They dismayed hardliner supporters with their willingness, firstly, to talk to the other side, and secondly, to then make painful compromises.