Sen. Joe Manchin, D-W.Va., stood alone. By the time the West Virginian announced he would support Brett Kavanaugh’s nomination to the Supreme Court on Friday, all the other incumbent red-state Democrats already said they were voting no.

This includes Sens. Heidi Heitkamp, D-N.D., and Joe Donnelly, D-Ind., both of whom share a couple of characteristics with Manchin: They are up for re-election this year in states President Trump won handily, and they voted to confirm Neil Gorsuch in 2017. Even one centrist Republican, Sen. Lisa Murkowski of Alaska, refused to vote for cloture.

When Kavanaugh was nominated, even some Democrats who voted against Gorsuch were thought to possibly be in play. Sen. Bill Nelson, D-Fla., was trailing Gov. Rick Scott in the polls and could display an independent streak by voting for a Trump judge. Sen. Jon Tester, D-Mont., was also looking to differentiate himself from the national party. Sen. Claire McCaskill, D-Mo., drew a considerably tougher opponent in Missouri Attorney General Josh Hawley than Todd Akin six years ago.

These red-state Democrats were feeling the squeeze: Vote against Kavanaugh and potentially turn out conservative voters against them; vote for Kavanaugh and alienate the outside liberal groups who are working to drag competitive Democratic candidates across the finish line in November.

Such a scenario has already played out for Manchin. Both he and Phil Bredesen, the popular former governor who gives Democrats a chance to pick up a Republican-held Senate seat in Tennessee, have been cut off by progressive groups Priorities USA and MoveOn.org in the wake of their support for Kavanaugh, while Senate Majority PAC is standing by them.

“We're cancelling a planned six-figure digital video ad expenditure for Phil Bredesen in Tennessee due to his Kavanaugh position,” tweeted MoveOn, a group originally founded to urge Washington to “move on” from allegations of sexual misconduct against President Bill Clinton. “And similarly will be pulling all planned campaigning on behalf of Joe Manchin in West Virginia if he votes yes. Kavanaugh is unfit for the Court.”

Manchin, who is leading in the polls, isn’t as dependent on liberal groups as other Democrats running this year. He does, however, have to worry about marginalizing himself within his party in between elections. The Congressional Black Caucus’ Twitter account noted that Manchin first voted to confirm Attorney General Jeff Sessions and then came out for Kavanaugh, asking, “With friends like these, who needs enemies?”

The sexual assault allegations gave vulnerable Democrats a way to argue that Kavanaugh was different than Gorsuch or some other hypothetical Trump nominee, perhaps even one from his list of potential Supreme Court picks, justifying their opposition without positioning themselves against conservative judges more broadly. “As I have made clear before, sexual assault has no place in our society,” Donnelly said in his anti-Kavanaugh statement. “When it does occur, we should listen to the survivors and work to ensure it never happens again. That should not be a partisan issue.”

But there have since been indications that the Kavanaugh fight has helped narrow the “intensity gap” between Democratic and Republican voters. This was seen both in a national survey by NPR/Marist as well as in Fox News polling of five competitive Senate races — Arizona, Indiana, Missouri, North Dakota, and Tennessee — which might explain why cagey politicians like Manchin and Bredesen made a different Kavanaugh calculation than Heitkamp, who suddenly looks like she is in real trouble.

Whatever “Kavanaugh effect” exists in the polls could dissipate by Election Day if the judge is confirmed, as now seems likely. Yet that may not be the case in red states where sitting Democratic senators have voted against Kavanaugh.

Republicans haven’t even stopped beating up on pro-Kavanaugh Manchin, who waited until Sen. Susan Collins, R-Maine, put the judge over the top to declare his intentions despite representing a state that went for Trump by 42 points. “Joe Manchin only votes in the interest of Joe Manchin,” GOP challenger Patrick Morrisey said in a statement. “President Trump had all the votes he needed to confirm Judge Brett Kavanaugh, but Manchin waited — making a craven political calculation — in order to try to save his political career.”

When Manchin was still sitting on the fence, Morrisey’s campaign called him “Sideline Joe.” Donald Trump Jr. mocked Manchin on Twitter, calling the West Virginia senator and former governor a “real profile in courage.”

“Waited until Kavanaugh had enough votes secured before he announced his support,” the younger Trump wrote. “I bet he had another press release ready to go if Collins went the other way.”

The fate of Democrats like Manchin could decide which party controls the Senate next year. “I say to the donor class and I say to others within the party, let’s not forget that we have some red-state Democrats, that whether you like them or agree with their ideology, they are valuable members of the Democratic caucus,” said one party strategist. “We have to do what we can to defend them as they try to win in Trump states …. These are seats that should we lose, it might be hard to regain them in the next several cycles.”