If there is one reason Senate Republicans decide to keep Brett Kavanaugh’s Supreme Court nomination on track despite a credible, on-the-record allegation of sexual assault when he was in high school, it’s this: the clock.

Specifically, the countdown clock until Election Day in November, when Republicans' majorities in both the House of Representatives and the Senate could be in peril. These next few weeks are the only time Republicans have to confirm Kavanaugh before, in a worst-case election scenario for the party, Democrats have more control over the process by winning back the Senate. It’s even possible that President Trump and Republicans never get to replace retired justice Anthony M. Kennedy with a conservative pick.

Here’s the timeline that is crunching Republicans: They had planned to start the voting process to confirm Kavanaugh on Thursday with a vote in the Senate Judiciary Committee. They had hoped to have Kavanaugh on the court by Oct. 1, which is when the new Supreme Court term starts. That would have given them a little more than a month to campaign on the success of firming up the court’s 5-to-4 conservative majority.

That’s no small thing in an election year in which Republicans need to rev up their base to counteract an activated left, especially given that, besides a tax bill, Republicans lack any other major legislative accomplishment to campaign on for their first two years controlling Washington’s power levers.

But if they pause Kavanaugh’s nomination — or scrap it all together — they risk handing over the process to Democrats. Right now, Democrats are heavy favorites to take back the House. In a really big blue wave, they could take back the Senate.

Let's say Democrats do have a fantastic midterm election and win the majority in the Senate.

If Republicans pause Kavanaugh’s nomination now, then decide to go forward with it after the election, they’d be operating as lame ducks, voted out of the majority by the American people. That’s not far off from the argument Republicans used to hold up President Barack Obama’s nominee to the Supreme Court, Merrick Garland, in 2016: The president was a lame duck, so let the American people decide who gets to sit on the court by way of the presidential election. (President Trump won, and Republicans got to put a reliable conservative vote on the court, Justice Neil M. Gorsuch, to replace the reliably conservative Antonin Scalia.)

Let’s take this a step further. If Senate Democrats have the majority when the new Congress starts in January, could they use that exact same argument to hold up this nomination process until the 2020 presidential election, where they hope to overthrow Trump? It’s a politically and constitutionally messy question, but it’s a path we could be heading down if Republicans pause or scrap Kavanaugh’s nomination and Democrats win back the Senate in a few months.

Plus, the longer this nomination is held up, the longer the allegations could simmer, and the more trouble Kavanaugh could be in. Kavanaugh denied the allegations by Christine Blasey Ford, saying in a statement Monday morning that “this is a completely false accusation.”

From The Washington Post’s Emma Brown, who talked to Ford:

While his friend watched, she said, Kavanaugh pinned her to a bed on her back and groped her over her clothes, grinding his body against hers and clumsily attempting to pull off her one-piece bathing suit and the clothing she wore over it. When she tried to scream, she said, he put his hand over her mouth.

Emma Brown, The Washington Post

As far as tracing decades-old sexual harassment allegations go, Ford’s story is remarkably credible. Ford is speaking on the record about her experience. She passed a polygraph test, the results of which The Post reviewed. She told other people about the alleged attack years before Kavanaugh was a Supreme Court nominee. She allowed her records from a therapy session about it to be reviewed by The Post. She says she didn’t want to come forward and decided to do so only after her story was leaked to news outlets.

Her story is credible enough that within 24 hours of sharing it, four Republican senators said the nomination should be paused. Just two defections would be enough to derail his entire nomination, an embarrassment that Senate Majority Leader Mitch McConnell (R-Ky.) desperately wants to avoid.

So then the question becomes whether Kavanaugh’s nomination will even proceed. It’s looking more possible that Ford will testify before the Senate Judiciary Committee, but what happens after that?

This allegation is serious and credible, and yet it’s notable that there’s no sign (yet) Republicans will pause the nomination over it. That’s a reflection of how under the gun they are to get on the court now or risk missing their chance forever.