Twelve Democratic candidates will duke it out 8-11pm ET Tuesday night in the fourth primary debate of the 2020 election season: Joe Biden, former vice president; Cory Booker, New Jersey senator; Pete Buttigieg, mayor of South Bend, Indiana; Julián Castro, former Housing and Urban Development Secretary; Kamala Harris, California senator; Amy Klobuchar, Minnesota senator; Beto O'Rourke, former Texas congressman; Bernie Sanders, Vermont senator; Tom Steyer, businessman; Elizabeth Warren, Massachusetts senator; Andrew Yang, entrepreneur; and Tulsi Gabbard, Hawaii congresswoman. The focus is expected to be on frontrunners Joe Biden, Elizabeth Warren and Bernie Sanders. Our guide spotlights each candidate, their faith traditions and how it impacts their politics.