But if the history of revolutions tells us anything, it is that rebuilding new political orders is a protracted, difficult, and unpredictable process, and having a few Mandelas around is no guarantee of success. Why? Because once the existing political order has collapsed, the stakes for key groups in society rise dramatically. The creation of new institutions -- in effect, the development of new rules for ordering political life -- inevitably creates new winners and losers. And everyone knows this. Not only does this situation encourage more and more groups to join the process of political struggle, but awareness that high stakes are involved also gives them incentives to use more extreme means, including violence.
This is why I remain optimistic about the Arab uprisings — not because they'll deliver immediate benefits, but because they broke a failing pattern of state-society relations. Seeing what's happened in Tunisia alone makes it all worth it. (Or to put it another way, the Terror and the rise of Napoleon and 15 years of European war do not make the French Revolution a bad thing.) Do read the whole thing which has a lot of examples from history.