By all accounts, Donald Trump’s Republican presidential campaign is imploding, with the latest revelations from a leaked 2005 “Access Hollywood” taping revealing not only Trump’s disrespect for women but a bragging about what amounts to a sexual assault. (Why anyone should be surprised by this given Trump’s previous statements and actions is something hard to fathom; take the latest expressions of shock with a huge grain of salt).

Hillary Clinton, who was already leading in the polls and seemed likely to continue her lead despite new leaked revelations that she supports free trade and is cozier with banks and big business than she’s admitted (again, no surprise there for anyone paying attention), seems now likely to prevail. Donald Trump has run the worst presidential campaign in modern history, judged only by the week after his poor debate performance featuring comments taking on a former beauty contestant as too fat, complaining about his microphone, supporting the convictions of the exonerated Central Park 5, and making new irresponsible claims about vote rigging and Mexicans coming across the border to vote). And all of that came before the “grab them by the pussy” comments came out.

Now, as the many members of the Republican establishment issue condemnations of him but still say they will vote for him and support his choice for the Supreme Court, a few are starting to break ranks, calling on him to withdraw.

What happens if he withdraws? Back in August, I wrote about how Republicans could name a replacement for him if his place was vacant, and that courts should bend over backwards to allow Republicans to list a replacement choice on the ballot so voters would have a meaningful choice. But now that option comes too late. Not only are absentee ballots out, many people have already voted. Election Day has passed for hundreds of thousands of people already. (That’s no reason to oppose early voting; most early voters are committed partisans, and few who voted for Trump already would likely have second thoughts now).

But if Trump withdraws, and in fact even if he doesn’t, there is one other possible way out: the Electoral College. When we cast our votes for president they are actually cast for electors from each state (based roughly on population size) who then cast ballots for president. If Trump is chosen in some states, those electors could vote for Pence, or Romney, or Kasich, or whoever. There are some laws that bar “faithless” electors from casting votes for anyone who did not win the popular vote in a state, but I have a hard time believing either the Republican-controlled House or a court (because it raises a political question) would stop the actions of a faithless elector. Ned Foley games out how conflicts would work under the Twelfth Amendment; the bottom line is that if Trump got more votes than Clinton and Republicans control we could well end up with a President Pence. (When no one gets a majority in the Electoral College the House votes on a one state delegation, one vote rule.)

The reason this is such a Hail Mary is because it depends on a huge number of unlikely contingencies: Trump withdraws or the Republican leadership abandons him yet still get voters to choose Trump on the ballot, the “Trump” campaign gets more electoral college votes than the Clinton campaign (requiring a lot of thinking and effort on the part of battered voters), electors chosen by the Trump campaign to serve the Republican ticket (some of whom LOVE Donald Trump) would act faithlessly and vote for Pence or someone else, and Republicans control the Senate. All of this is possible, but not bloody likely.

That’s why the more plausible scenario is the following: after tomorrow’s debate, when Trump does not do well, some in the Republican leadership start withdrawing their endorsements. Watch Ryan move before McConnell, because Ryan has presidential aspirations of his own. Trump is essentially left twisting in the wind. The big message from Republicans is to vote for Republicans in the U.S. Senate to block Hillary Clinton from getting her agenda passed. More money from the Koch brothers, Sheldon Adelson and other plutocrats floods into the Senate races, which right now are very close on the question of control. And the more that Republican Senate candidates can distance themselves from Trump, the more likely it is that swing voters split their tickets and vote for the Republican Senate candidate.

The end game now is about denying Clinton control of the Senate, and with that comes loss of a free hand to choose a Supreme Court nominee (because if Democrats take even one seat of control, I expect they will nuke the filibuster to put in whoever they want for the Supreme Court). As I argued a year ago, the Supreme Court is the most important civil rights issue of our time: “The future composition of the Supreme Court is the most important civil rights cause of our time. It is more important than racial justice, marriage equality, voting rights, money in politics, abortion rights, gun rights, or managing climate change. It matters more because the ability to move forward in these other civil rights struggles depends first and foremost upon control of the Court. And control for the next generation is about to be up for grabs, likely in the next presidential election, a point many on the right but few on the left seem to have recognized.”

There’s so much at stake even if, as expected, Trump continues to implode.