WATCH: Former GOP Senator Flake Endorses Biden. MacCallum Grills Him.

On Monday, speaking of the 30 former GOP legislators who have endorsed Joe Biden, Fox News host Martha MacCallum interviewed one of them: former GOP Arizona Senator Jeff Flake, inducing him to consistently deflect as she pressed him on how a lifelong Republican could support someone sworn to a progressive agenda.

MacCallum started, “You once wrote an op-ed, by the way, that was urging lawmakers to abandon the president and ‘save your soul,’ which we all remember well, and I think we spoke to you about that back then. But my question for you tonight is that with regard to Joe Biden, he has said that ‘If I’m elected, I will be the most progressive president in history.’ How do you, as a lifetime Republican, support someone who has that goal?”