Senator Joe Manchin III, Democrat of West Virginia, does not plan to run again for his old job as governor and will remain in the U.S. Senate. Manchin had been toying for most of the summer with a possible campaign for his old job, which he left in 2010 after winning a special election for the Senate seat of the late Senator Robert C. Byrd, also a Democrat.

In a statement released Tuesday, Manchin's enthusiasm for the top executive office in the state was clear. He said that serving as governor had been the "greatest honor of my life" and "[n]othing made my heart swell with pride more than bragging about the wonderful state I represented."

But he went on to say, ""I have always said that 'public service is not self-service.' So, when considering whether to run for Governor, I couldn't focus just on which job I enjoyed the most, but on where I could be the most effective for the Mountain State."

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And it's his role as senator, he said that "allows me to position our state for success for the rest of this century." He vowed to use his influence as the top Democrat on the Energy and Natural Resources Committee to make energy technology investments that build an energy base for the nation that "protects jobs, keeps prices low, and recognizes the reality of climate change."

The decision means Manchin, one of the few bipartisan power brokers left in the sharply divided Senate, will remain in Washington as a potential emissary between the two parties on tricky issues including gun control and other domestic issues.

But Manchin hasn't shied away from criticizing his own party for its leftward lurch and is expected to continue expressing concerns with the campaigns and viewpoints of liberal presidential candidates, including his Senate colleagues Bernie Sanders, independent of Vermont, and Elizabeth Warren, Democrat of Massachusetts. In his statement Tuesday, he reiterated that he would continue to work with the president and "speak truth to power" when he doesn't agree with President Trump.

Manchin's decision was not an obvious one: CBS News reported that aides to Manchin were preparing drafts of two possible statements late Monday: One that signaled his intention to stay in the Senate and another announcing plans to run again for governor.

Manchin won re-election to the Senate last year by barely 3 points, capitalizing on his reputation as a moderate Democrat and as one of the only members of his party in regular contact with Mr. Trump, even as his state becomes more Republican.

Despite his bipartisan position of influence on Capitol Hill, Manchin has always maintained that he much preferred serving in an executive role as governor. He was elected to the role in 2004 and was re-elected in 2008. West Virginia law allows him to run again.

Manchin is a former friend-turned-foe of current Republican Governor Jim Justice, who won in 2016 as a Democrat but switched parties two years ago at the urging of Mr. Trump. The senator has been outspoken in his criticism of the sitting governor in recent months and welcomed speculation he might run again for his old job.

"I've had a lot of inquiries they want me to come back home," Manchin told "Face the Nation" on August 18. "I have people think that maybe I should stay."

Manchin, 72, joined the Senate in 2010, succeeding Byrd, and quickly became a liaison between the two parties. His knack for bipartisan deal making emerged especially during the 2013 debate over gun control legislation after the 2012 Sandy Hook, Connecticut school shooting left 20 schoolchildren dead. Although his bipartisan plan to expand the national gun background check system failed to pass, members of both parties credited him with leading the debate.

In the years since, he's been a vocal critic of leaders in both parties and regularly draws the ire of liberal, or more partisan Democrats, for touting his partnership with Republicans or supporting GOP causes, including voting for Mr. Trump's Supreme Court nominees, Neil Gorsuch and Brett Kavanaugh.

More recently, partisan Democrats have attacked him for endorsing the reelection of Sen. Susan Collins, Republican of Maine, one of his frequent GOP collaborators.

"I can't believe everyone's so damn hypocritical. She's the one person I work with all the time," Manchin told Politico last month about his endorsement. "Why would you not expect me to do that?"