Last week on our show, Bob spoke with Lilliana Mason, a University of Maryland political psychologist and author of Uncivil Agreement: How Politics Became Our Identity, about the reasons behind the tribalism and enmity that characterize our politics. The conversation covered a lot of ground, and much of it — including the political decisions that have shaped the two major parties over the past 50 years, as well as the distinct ways that Republicans and Democrats deploy partisan rage — didn’t make it into our tightly packed show. But, it’s too interesting and important to leave on the cutting room floor, so we’re sharing it as this week’s midterm edition podcast extra. Enjoy!