I’ve always liked this one because, if you think about it, it really sums it all up. Systems, like communism or naziism, which are based on One Answer to all questions are, sooner or later, going to meet with a question they cannot answer. Democracy, which (properly understood, is simply pluralism), always has, somewhere, the answer to the question no one had earlier thought of.

History proves all dictatorships, all authoritarian forms of government are transient. Only democratic systems are intransient.

История убедительно свидетельствует, что все диктатуры, авторитарные системы правления преходящи. Непреходящей оказываются только демократические системы.

Putin “Russia at the turn of the millennium”, 1999, http://pages.uoregon.edu/kimball/Putin.htm