Democrats want to get a replacement candidate in place in time to be competitive in November.
Sen. John Walsh said Thursday he is pulling out of the Senate race because his campaign was distracted by the controversy over allegations that he plagiarized a U.S. Army War College research paper.
Walsh, a Democrat, said he decided to drop out of the race after canceling campaign events this week so he and his family could gather in his Helena home to decide his political future.
Walsh will serve out the rest of his Senate term, which ends in early January 2015.
The New York Times reported July 23 that Walsh had plagiarized large portions of the research paper in 2007.