It's tempting to explain Russia's invasion of Ukraine with Putin's megalomania. Economist Chris Blattman of the University of Chicago talks about his book Why We Fight with EconTalk host Russ Roberts. Blattman explains why only a fraction of rivalries ever erupt into violence, the five main reasons adversaries can't arrive at compromise, and the problem with trying to get into Putin's head (and why it's not all about Putin. Really).