Sen. Joe Manchin III, a Democrat, announced Tuesday that he will stay in the Senate and not run for governor in West Virginia, passing on a challenge to a Republican incumbent strongly backed by President Donald Trump.

Manchin, 72, served as governor from 2005 to 2010, and last year considered retiring from the Senate before reluctantly agreeing to seek reelection in a state that Trump carried handily in the 2016 presidential race. He was narrowly reelected to a six-year term.

After months of publicly musing about making another gubernatorial bid, Manchin, considered the most conservative Democrat in the Senate, said he thought he could be more effective by staying there.

“(W)hen 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,” Manchin said in a statement. “Ultimately, I believe my role as U.S. Senator allows me to position our state for success for the rest of this century.”

He cited his role as the top Democrat on the Energy and Natural Resources Committee, as well as his work on military issues and making “sure that West Virginia gets its fair share of federal resources.”

“I will work with the President to accomplish what best serves our state and our country and I will speak truth to power when I don’t agree with the path the President has chosen to take – that is what West Virginians elected me to do!” Manchin said.

Manchin echoed those points at a news conference early Tuesday afternoon in Charleston, West Virginia, where he relayed that he had reached a final decision the day before.”I’m at peace, I’m at ease with this,” he said, also lamenting how few lawmakers from either party remain in the “middle” these days.

Manchin has sought to reach across the aisle to work with Republicans on legislation, including on background checks for gun purchasers. He was the only Democrat to break from his party in voting to confirm Brett Kavanaugh to the Supreme Court last year.

West Virginia Gov. Jim Justice, a billionaire businessman, was elected in 2016 as a Democrat. Less than a year later, he announced at a Trump rally in his state that he was switching parties.

He has since declared that he and Trump are “bound at the hip.”

Manchin had earlier called the West Virginia governorship the “best job in the world.” He has not shied away from expressing his frustrations with the nation’s capital, including in a campaign ad last year in which he said “Washington sucks.”

Manchin won re-election last year against Attorney General Patrick Morrisey, a Republican, by 3 percentage points in a state that Trump carried in 2016 by 42 percentage points.

Appearing on the West Virginia ballot during the same year in Trump could pose a greater challenge, given the number of voters who cast ballots for straight-party tickets.

Manchin does not face re-election to Senate until 2024.