Democrats secured the votes on Monday to filibuster President Donald Trump’s Supreme Court nominee, Judge Neil Gorsuch, later this week. But four of their senators—Joe Manchin, Heidi Heitkamp, Joe Donnelly, and Michael Bennet—won’t be joining in the resistance. These centrists are trying to avoid total opposition to Donald Trump, in part because they’re fearful of being punished by voters at home (especially Bennet, of Colorado, where Gorsuch is from).

The notion that opposition might imperil these senators, risking further depletion of the Democratic caucus in the 2018 midterm elections, is the only reason progressives could live with their defections. There’s just one problem. According to the former dean of the Supreme Court press corps, senators’ votes on Court nominees have seldom made a difference for them electorally.

“I honestly don’t know of any circumstance where somebody gained a seat or lost a seat in the Senate based on the position they’d taken on a Supreme Court nomination,” said Lyle Denniston, who has reported on the Court for almost six decades, including 12 years at SCOTUSblog. Even in this hyper-partisan moment, Denniston told me, “I find it very hard to imagine, with all of the other issues surrounding a senatorial election, that the Supreme Court will be decisive.”

It’s not just Denniston who sees it this way.

“I can’t think of an example of a senator who lost an election or really got into deep trouble on a Supreme Court nomination,” American Enterprise Institute scholar Norm Ornstein said. “I can’t think of one,” echoed Bob Shrum, the longtime Democratic strategist.