No one can ever understand the moment of revolution. Everything that could have provoked an uprising in Egypt has been present, and not acted upon, for decades. Yet, as often happens, a relatively minor incident, the suicide of a young man in Tunisia, began it all, rallying Tunisians from different political and social backgrounds. We do not know where and how this will spread, which regimes will fall. (All commentators have noted that the Islamist movements have failed to gain the upper hand.) But the "Arab exception" will not last much longer.