MISSOULA, Mont. -

Montana Sen. John Walsh is leaving the U.S. Senate race amid allegations that he plagiarized a thesis paper at the U.S. Army War College in 2007.

Montana's Democratic Party now has until Aug. 20 to submit the name of a replacement candidate to the secretary of state.
    
Walsh's thesis written for the U.S. Army War College contained unattributed passages that appear to be taken word-for-word from previously published papers. Walsh's thesis appears to borrow heavily from a Carnegie Endowment for International Peace Paper written in 2002. One paragraph from the Carnegie paper that offers advice on how to promote democracy in the Middle East is copied verbatim into Walsh's thesis.

When NBC Montana spoke to Walsh via phone in July, he said, "I made a mistake on the paper; I admit that. You know, now I'm going to focus on what's important to Montanans, and that's fighting for jobs, making sure our public lands remain in the hands of Montana and looking after women's health care issues."

Democratic Gov. Steve Bullock appointed Walsh in February to replace Sen. Max Baucus, who was appointed U.S. ambassador to China.

Walsh served 33 years in the Montana National Guard. He was the state's adjutant general when Bullock, then attorney general, tapped him to be his running mate in the 2012 governor's race.

Walsh served as lieutenant governor, his first elected position, for just over a year before his Senate appointment.

Montana Democratic Party Statement on Walsh withdrawing:

 
The Montana Democratic Party released the following statement after the announcement that Senator John Walsh will be withdrawing from the U.S. Senate race:
 
“Senator Walsh's life has been and continues to be service to our nation and all Montanans.  From 33 years in the National Guard, to serving as Lt. Governor to his time in the U.S. Senate, John Walsh has sacrificed significantly for our country and is to be commended. 
 
“The Montana Democratic Party looks forward to an open and transparent opportunity for Democrats to come together to decide our new nominee. As we move forward in this race, we must remember this election is not about one person; it’s about Montana. This election is about ensuring our public lands aren’t sold off to the highest bidder, women are free to make their own health care decisions, every Montanan has the opportunity to succeed, and our kids and grandkids are not denied quality education,” said Jim Larson, Chair of the Montana Democratic Party.
 
The Montana Democratic Party’s rules for filling a vacancy for statewide office can be found here.

Walsh sent the following note to supporters:

Montanans,

Nothing is more important to me than serving the people of Montana. It’s been my privilege for more than 30 years, defending both our state and nation.

The 2007 research paper from my time at the U.S. Army War College has become a distraction from the debate you expect and deserve. I am ending my campaign so that I can focus on fulfilling the responsibility entrusted to me as your U.S. Senator. You deserve someone who will always fight for Montana, and I will.

I am proud that with your support, we held our opponent accountable for his hurtful record to privatize Medicare, to deny women the freedom to make their own health decisions and to sell off our public lands. I know how important it is to continue the fight for these Montana values, and it is time for us all to return to the real issues of this election.

I am grateful for the opportunity to have met countless people in the course of this campaign who have offered support – who know what’s at stake for the future of our great nation.  That is why public service is so important to me, and why I look forward to continuing to fight for Montana in the U.S. Senate.

Sincerely,

John Walsh

Senator Jon Tester today released the following statement on Walsh:

“I respect Senator Walsh's decision to step out of the race, I know it was a difficult one.  John has dedicated his life to serving the people of Montana and our country.  From his 33-year career of military service to his work in the U.S. Senate, John Walsh has courageously devoted himself to our state and our nation and we all owe him thanks for his service.”

The following statement was released by Rep. Steve Daines:

"I respect Senator Walsh's decision. I remain focused on working for the people of Montana and fighting for more jobs, less government."