As you’ve probably heard by now (we had it in the headlines yesterday), Sen. Joe Manchin is not running for another term in the Senate next year. Manchin would be running as a Democrat in West Virginia against Gov. Jim Justice, a popular Republican.

This move makes a lot of sense for Manchin. Rather than spend time and money only to lose a race he has little chance of winning, Manchin gets to go out on his own terms. But there’s no denying this is very bad news for the Democratic Party. In order to hold the Senate, they now need to win every seat they are defending and win the White House.

The path to holding power was always going to be rocky for the Democrats’ current 51-seat majority, with or without Mr. Manchin.

Two incumbents are running for re-election in red states, Montana and Ohio. A third senator, Kyrsten Sinema of Arizona, who was elected as a Democrat but has since switched her party affiliation to independent, has yet to declare her plans — leaving open the prospect of an unusually competitive three-way race. And the party must also defend four Senate seats in four of the most contested presidential battlegrounds: Wisconsin, Nevada, Pennsylvania and Michigan.

With West Virginia off the Senate chessboard next year, Democrats must win every race they are defending — and depend on President Biden to win the White House — in order to maintain a majority. In a 50-50 Senate, the vice president casts the tiebreaking vote. But that’s a risky bet considering a plurality of Americans haven’t approved of President Biden since August 2021, according to Gallup polls.

The math is so daunting that the White House apparently begged Manchin to run again.

As Sen. Joe Manchin struggled for several months over the next step he would take politically, President Joe Biden’s top advisers privately tried to persuade him to run for another term in the Senate.

Multiple West Wing aides, including senior counselor Steve Ricchetti, and some outside Biden allies talked with the West Virginia Democrat, according to two White House officials and another adviser who were granted anonymity because they weren’t authorized to publicly discuss the conversations. Their pitch to Manchin was that, while a reelection bid in a deep-red state would be difficult, he had a path to victory.

Manchin’s decision not to run is a problem but there’s an even more worrisome possibility that White House advisers are now worried about. What if Manchin decided to run for president?

…the fact that Manchin is actively being encouraged to seek a presidential run sparked new anxiety among Democratic operatives who were already concerned about the impact of third parties in 2024. Progressive activist Cornel West and Robert Kennedy Jr., an environmental lawyer and leading vaccine skeptic, have already launched independent White House runs.

Yet many Democratic leaders are taking No Labels more seriously. Backed by anonymous donations of tens of millions of dollars, the centrist group has already secured presidential ballot access in a dozen states with many more expected over the coming months. Its officials say it will decide early next year whether to launch a presidential ticket.

“If Joe Manchin runs on the No Labels ticket, he would be responsible for sending Donald Trump back to the White House,” MoveOn Political Action executive director Rahna Epting said shortly after Manchin’s announcement. “Joe Manchin should set the record straight on whose side he is on and reject any overtures from No Labels’ dangerous ploy.”

Polls show Biden is still struggling with very low approval ratings. The last thing he needs is a center-left spoiler candidate who could peel off a few percentage points from his totals. If it were anyone else, I’d assume party loyalty would come into play and keep him out of the race, but Manchin has been bucking his party for a long time. He may just succumb to the allure of a presidential race.

Also, you’d think a guy who isn’t anywhere close to as well known nationally as Biden couldn’t do much damage, but poll after poll has showed a lot of Democrats are eager for someone else to run. In this environment there’s no telling what could happen. Biden might actually lose more than a few points in some places.

This really looks like an opportunity for Republicans to reclaim the Senate but never underestimate their own ability to botch it.