(CNN) An allegation of a sexual assault and a take-it-or-leave it offer to the accuser to testify ASAP have opened a new partisan divide and thrown the Supreme Court nomination of Brett Kavanaugh, which had seemed to be on a glide path, into chaos.

Whether a new hearing, tentatively planned for Monday, takes place and who testifies are very open questions at this point. Kavanaugh and California professor Christine Blasey Ford, who alleges that a drunken Kavanaugh physically and sexually assaulted her when they were both in high school, could both testify. Kavanaugh denies the allegation.

Republicans have framed it as a take-it-or-leave-it opportunity for Ford to make her case. Ford has said there should be an FBI investigation of the claims first. Remember, Republicans want this to happen very fast, which is why Judiciary Committee Chairman Chuck Grassley rushed a hearing date onto the calendar. Democrats like Sen. Dianne Feinstein, who Ford first notified about the alleged attack, wouldn't mind it dragging out.

Why? Election Day. The current Senate becomes a lame duck in November and goes away entirely in January. There are almost too many variables to keep track of, but here are some ways the Kavanaugh story could play out:

Scenario 1: Republicans rally, confirm Kavanaugh

If the hearing goes forward and Ford is not believable or if it is canceled because she won't testify, there's a decent chance Republicans could rally around Kavanaugh and confirm him. Both Maine Sen. Susan Collins and Alaska Sen. Lisa Murkowski, two Republicans who said they want to hear Ford's side, suggested it would be very interesting indeed if Ford did not make her allegations in public on Capitol Hill.

Scenario 2: Pence casts tie-breaker, confirms Kavanaugh

In the current Senate, two Republicans and every Democrat would have to oppose Kavanugh to put his nomination in actual jeopardy. If only one Republican opposed Kavanuagh, like Collins of Murkowski, but every other Republican supported him, Vice President Mike Pence would have to cast a tie-breaking vote. It would be unprecedented for a Supreme Court justice with a lifetime appointment to be confirmed in such a way, but Republicans already changed Senate procedure requiring 60 votes to limit debate on Supreme Court nominees in order to confirm Trump's earlier pick, Neil Gorsuch. Would they hold back on a tie-break? Nope. Probably not. At the same time, being the only Republican to oppose a Supreme Court nominee would be a very lonely place to be.

Scenario 3: Kavanaugh fails, Republicans find a new nominee before Election Day

If Kavanaugh's nomination does falter, there's little time for Republicans to push another nominee through before the election. In earlier eras, Supreme Court nominations would take just a few days. No more. Most recent nominations take more than two months from nomination date to confirmation. Kavanaugh, who was nominated July 9, is already beyond that. We're less than two months to Election Day right now. Any new nomination would have to be done with speed unlike any we've seen in recent years. The last successful nominee who was confirmed in less than a month was John Paul Stevens, nominated by President Gerald Ford in 1975.

Note: We've now reached Election Day, after which there will be the promise of a new Senate, so the scenarios now rely on either a Republican or Democratic majority.

Democrats have a difficult path to regaining control of the Senate, but it's not entirely out of the realm of possibility.

Scenario 4: Kavanaugh fails, Republicans vote on a new nominee in the Lame Duck

If Republicans keep their Senate majority or expand it, confirming a nominee after Election Day won't be much of an issue. But if Democrats take the Senate in November, would Republicans rush a conservative nominee through before Democrats took control in January?

McConnell would probably not mind that hypocrisy one bit. (He sat on Garland's nomination because it was a presidential election year and this is a midterm year.) But we're talking about replacing swing vote Anthony Kennedy with a rock-ribbed conservative here. That's a generational accomplishment.

Whether his entire Republican flock followed him would be another question. If Democrats take control of the Senate, it's possible some Republicans might not be able to stomach confirming a lifetime judge after a rebuke at the ballot box. But, and this bears repeating over and over, these nominations are about having a conservative majority for decades or not. You can imagine most Republicans living with it. This would be uncharted territory.

Scenario 5: Kavanaugh falters, Democrats win Senate Majority, find consensus nominee

Let's say, somehow, Republicans are unable to confirm Kavanaugh or some other replacement nominee after losing the election and Democrats take over. Would Democrats want to play nice and work with President Trump and Republicans to find a nominee everyone can agree on? President Trump has vowed to select his nominees from a conservative-approved list that does not sit well with Democrats. It's hard to imagine a consensus nominee in this scenario, when the ideological bent of the court is on the line.

Scenario 6: Kavanaugh falters, Democrats win Senate majority, but block a nomination until 2021

If Republicans fail to get a nominee through and Democrats take control of the Senate, the Democratic base will be lobbying hard for their lawmakers to sit on the nomination until after the next presidential election.

"I think we've had those kinds of vacancies before, and we certainly had over a one-year vacancy with Merrick Garland," Hawaii Sen. Mazie Hirono, a Democrat on the Judiciary Committee , told Politico Magazine. "So the world does not come to an end because we don't fill all of the nominees."

At that point you'll be reading all sorts of stories about how there's nothing in the Constitution about there being nine justices on the Court. There have, in US history, been periods without nine justices, with six and 10. Congress put language in the Judiciary Act of 1869 setting the number of justices at 9, but there's nothing in there about how long a vacancy could last.

Following this scenario, there could be no new justice for years, potentially not until a president had a friendly Senate. Given how often Democrats still mention Garland and complain about McConnell's delay, it's not completely out of the question.