If Susan Collins announces for Brett Kavanaugh, the game’s over. Photo: Andrew Harrer/Bloomberg via Getty Images

The Senate math for Democrats fighting to defeat confirmation of Brett Kavanaugh as a Supreme Court justice was originally straightforward if daunting: flip one of two pro-choice Senate Republicans (Collins and Murkowski) and hold all the Democrats, and the deed would be done. Senate Democratic leader Chuck Schumer asked vulnerable red-state Democrats up for reelection this year (especially Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, and Joe Manchin of West Virginia, who all voted to confirm Neil Gorsuch last year) to “keep their powder dry” as long as possible to determine if their votes even mattered. And some progressives criticized Schumer for this “catch-and-release” strategy, arguing that solidifying the Democratic caucus first would make it possible to bring the hammers of hell down on Collins and Murkowski as each being potential deciding votes.

But then something very big happened that oddly enough has been underappreciated in its impact on the Kavanaugh confirmation fight: John McCain died, and Jon Kyl was appointed to take his seat. Since McCain had been absent from the Senate most of the year due to illness, Republicans could not afford to lose more than one senator on a tough vote like this one. Kyl was actually Kavanaugh’s “sherpa” (a senior party figure designated to guide a nominee) during the confirmation process, so he will be there with bells on to vote for the judge. And thus the scenario in which Democrats could go after Collins and Murkowski individually as the “deciding vote” has evaporated. They now must flip both Republicans before any of the red-state Democratic senators matter at all. And that means the moment either Collins or Murkowski announces for Kavanaugh, it’s game over. It’s a subtle but crucial difference from the situation before McCain died.

Progressives inclined to place pressure on Donnelly, Heitkamp, and Manchin (or for that matter, Alabama’s Doug Jones or Montana’s Jon Tester — there are many cats that must be herded to keep the caucus intact) should take this change of circumstances fully into account. The odds of defeating this confirmation have gone down significantly, not only because Kavanaugh got through his interrogation in the Judiciary Committee without any big revelations, but because Republicans can now afford to lose a senator without losing the vote.

To some extent this has become a game of chicken: how long can the red-state Democrats stay on the fence, and how late in the process can Collins and Murkowski delay their announcements? Murkowski has indicated she probably won’t tip her hand until right before the Senate vote, which would be consistent with her habit in the past of pursuing concessions before deciding whether to put on the party harness. She may also be more “gettable” for Kavanaugh opponents because she has reasons beyond abortion policy to worry about him: Native Alaskans fear he’ll vote to kill fishing rights they rely on in a case that could reach the Supreme Court almost immediately after he would join the Team of Nine (as he insisted on calling it through his hearings).

But to the extent that at least one of these two Republicans is very likely to vote for Kavanaugh, progressive groups need to reconsider the costs of making this a litmus test for Senate Democrats. As Mike Tomasky, no centrist squish, said in a New York Times op-ed, it may make little sense:

You have to look at the situations these people find themselves in, consider their re-election prospects — and consider the alternative. Take Mr. Manchin, whose circumstance is the one I know best.

He’s running for re-election in a state, my home state, where Mr. Trump is still enormously popular. Yet, Mr. Manchin is around eight points ahead of his Republican opponent, Patrick Morrisey, the state attorney general. Right now, Mr. Morrisey hasn’t yet quite found a theme on which to hammer Mr. Manchin.

But if Mr. Manchin were to cast a (numerically meaningless!) vote against Mr. Kavanaugh — presto. The rest of the race would be about that, and nothing but that. Millions of dark money dollars would pour in for TV ads blasting Mr. Manchin for going against the wishes of their president.

Yes, there is one dubious poll from Indiana showing that another highly vulnerable red-state Democrat, Joe Donnelly, would actually do better in November if he voted against Kavanaugh. But in general, national groups should not second-guess Democratic senators’ own assessments of what they need for political survival.

So at present the smart Democratic strategy is to focus with the light and heat of a thousand suns on Susan Collins, who will probably announce her decision on Kavanaugh earlier rather than later. Assuming she wants another term in the Senate in 2020, she may be most concerned about heading off a conservative primary challenge from Maine governor Paul LePage (who is term-limited this year) or someone of his abrasively conservative ilk. That’s why the initiative to crowdfund a Democratic opponent for Collins if she votes for Kavanaugh — which has already raised nearly $900,000 — is a smart move.

And if she decides to vote for Kavanaugh anyway, then as Tomasky notes, it really doesn’t matter if “he has 51 votes or 56.” The only rationale for going after red-state Democrats in that case would be as part of a drive for ideological and partisan purity in the Democratic Party. And at that point progressives need to seriously ask themselves if more left-bent candidates are likely to win in states like North Dakota and West Virginia in the foreseeable future.