One of the worst-kept secrets in national politics was officially revealed late yesterday when Arizona’s 9th District Rep. Kyrsten Sinema announced she was running for the U.S. Senate seat currently held by Jeff Flake.

Flake is considered to be an extremely weakened incumbent, drawing criticism from his right and left. And his disagreements with President Trump were exacerbated by his recent book, "Conscience of a Conservative: A Rejection of Destructive Politics and a Return to Principle."

At this point, he’s facing a primary challenge from former State Sen. Kelli Ward, but other Republicans may jump in.

With me to talk about Sinema’s decision and Flake’s future is Nathan Gonzales, editor and publisher of Inside Elections.