Flake, R-Arizona, was a U.S. Senator from 2013 to January 2019, and declined to run for re-election. Previously, he served in the U.S. House from 2001 to 2013. Currently, he is a contributor to CBS News and partners with CBS on a series called “Common Ground.” Flake is also the author of “Conscience of a Conservative: A Rejection of Destructive Politics and a Return to Principle.”