On Friday, federal authorities arrested Cesar Sayoc Jr. in connection with the pipe bombs mailed to some of President Trump's most vocal critics. NBC News political correspondent Steve Kornacki joins us to discuss what the bomb scare says about the polarization of American politics, which is the topic of his new book, “The Red and the Blue: The 1990s and the Birth of Political Tribalism." We'll also talk to him about Saturday's mass shooting at a synagogue in Pittsburgh and last week's murder of two people at a grocery in Louisville, which is being investigated as a possible hate crime.
NBC's Steve Kornacki on 'Political Tribalism' and a Nation on Edge
Steve Kornacki is the author of "The Red and the Blue: The 1990s and the Birth of Political Tribalism." (Photo: Art Streiber/MSNBC News)
Steve Kornacki, national political correspondent, NBC News; author, "THE RED AND THE BLUE: The 1990s and the Birth of Political Tribalism"