KEY POINTS
  • Maine House Speaker Sara Gideon will run for Senate in Maine in the race to unseat Republican Sen. Susan Collins. 
  • Democrats see Maine as one of their best chances to defeat a Republican incumbent in 2020 as they try to pick up four GOP-held seats and control of the chamber. 
  • Collins, who has tried to craft a bipartisan reputation, has faced furor from both her left and right over her vote to confirm Supreme Court Justice Brett Kavanaugh and her opposition to an Obamacare repeal plan. 
Sen. Susan Collins (R-ME) speaks to reporters as she arrives for a nomination vote on Capitol Hill in Washington, December 13, 2017.

Democratic Maine House Speaker Sara Gideon will run for U.S. Senate, giving endangered Republican Sen. Susan Collins her most notable challenger yet in a growing field.

Gideon, 47, announced her candidacy Monday morning. In a video, she touted efforts to work with the GOP in Maine and targeted Collins for backing the 2017 Republican tax law and voting to confirm Supreme Court Justice Brett Kavanaugh.