Sen. Joe Manchin announced Tuesday he planned to stay put in the Senate and not run for West Virginia governor, spelling relief for Democrats who now see a pathway to taking the Senate majority in 2020.

“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,” said Manchin, a Democrat who previously served as the state’s governor.

“Ultimately, I believe my role as a U.S. senator allows me to position our state for success for the rest of this century.”

Manchin entered the Senate in 2010 and ran for re-election last year. He squeaked out a win against Republican Patrick Morrisey, the state’s attorney general, with 49.5 percent of the vote.

Republicans were licking their lips at the prospect of easily replacing Manchin in the Senate as the state has progressively gotten more red. West Virginia voted for President Trump by a margin of 42 points.

The rest of the Senate map for 2020 has recently gotten tougher for the GOP. Democrats only need to pick up four seats — three if their candidate wins the White House — to take the majority.

Democrats’ primary targets are taking out Republicans in Colorado, Maine and Arizona. Former 2020 hopeful and ex-Colorado Gov. John Hickenlooper has announced his intentions to run for Senate against Republican Sen. Cory Gardner, known for working across the aisle on such things as the 9/11 Victim Compensation Act bill.

Democrats also want to wipe out swing vote Sen. Susan Collins (R-Maine), pointing to her decision to vote in the affirmative for Supreme Court Justice Brett Kavanaugh’s nomination.

And Democrats are hoping to repeat their luck in Arizona, as Sen. Kyrsten Sinema (D-Ariz.) already beat Sen. Martha McSally (R-Ariz.) once. McSally was later appointed to Arizona’s other Senate seat, though she faces re-election next year.

The Democrats also are looking to Texas, North Carolina and Georgia — with Republicans now having to defend both Senate seats in Georgia thanks to the news of Sen. Johnny Isakson’s retirement last week.

There are a number of states that could be surprises too, including Montana, Kentucky, Kansas and South Carolina.

The Democrats will have to defend some tough seats too, including Sen. Doug Jones’ in Alabama, which he won in a special election upset in December 2017.

In New Hampshire, incumbent Democrat Jeanne Shaheen could face President Trump’s ex-campaign manager Corey Lewandowski as a challenger.