Anatol Lieven is Senior Associate for Foreign and Security Policy of the Russian Eurasian Center at the Carnegie Endowment for International Peace in Washington, D.C.

The 20th century was notable for two enormous tyrannies: Nazism and Communism. Now a debate has surfaced over which system produced the greater evil. In this conversation, author Anatol Lieven argues that Nazism's commitment to genocide made it indisputably the worst offender.