It's tempting to explain Russia's invasion of Ukraine with Putin's megalomania. Economist\xa0Chris Blattman of the University of Chicago talks about his book\xa0Why We Fight with\xa0EconTalk 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).