U.S. Rep. Martha McSally, Congressional District 2, has told Republican colleagues that she will enter the race for the U.S. Senate seat being vacated by fellow Republican Jeff Flake, a move that puts a mainstream candidate who could win backing from President Donald Trump into the primary race.

Arizona Republican Sen. Jeff Flake’s re-election race is becoming a case study in the GOP’s convulsions among the establishment, a furious base and angry donors.