Sen. Jon Tester (D-Mont.)

Jon Tester has been serving as a Senator from Montana 2007. Prior to serving in the Senate, Tester was a member of the Montana Senate and a music teacher. As a Senator, Tester has focused on issues such as veterans’ affairs, agriculture, and healthcare. He is known for being a moderate within the Democratic Party and has often been willing to work with Republicans on legislation, which like Sen. Machin and Sen. Sinema, has somewhat made him an outcast from the Democratic party.

Tester is also the lone Democrat in a deep red area, like Manchin. While Tester stated that he believes that he’d win a fourth term if he runs, he hasn’t stated whether or not he’ll be running.