UPDATED: Here's The Hill's list of Republicans "disendorsing" Trump, doubling down on previous refusals to endorse him in the first place, and more. It contains some folks not mentioned below in my original write-up.

The release of an audio tape in which Donald Trump outlines what amounts to a practice of sexual assault on women, top Republicans are rejecting the billionaire developer in ever-larger numbers, with more than a dozen U.S. senators saying they will not vote for him and other members of the party demanding he step down as the GOP nominee for president. Since Matt Welch noted scathing attacks on Trump by the likes of Republican Sens. Mike Crapo, Jeff Flake, and Mike Lee less than 24 hours ago, the list has easily more than doubled. Here's a list put together by the BBC of leading Republicans who have publicly denounced their party's nominee for president:

Senators:

Susan Collins, Maine senator

Dan Sullivan, Alaska senator

Lisa Murkowski, Alaska senator

Kelly Ayotte, New Hampshire senator

Jeff Flake, Arizona senator

Dean Heller, Nevada senator

Mark Kirk, Illinois senator

Ben Sasse, Nebraska senator

Mike Crapo, Idaho senator

Cory Gardner, Colorado senator

Lindsey Graham, S Carolina senator

John Thune, S Dakota senator

Deb Fischer, Nebraska senator

John McCain, Arizona senator

Others:

Jeb Bush, former Florida governor

Tim Pawlenty, former Minnesota governor

Gary Herbert, Utah governor

Jason Chaffetz, Utah congressman

Carly Fiorina, former presidential candidate

Barbara Comstock, Virginia congresswoman

Mike Coffman, Colorado congressman

Mike Lee, Utah congressman

William Cohen, former secretary of defence

Michael Hayden, former CIA director, former NSA director

John Kasich, Ohio governor, 2016 presidential candidate

Tom Ridge, former Pennsylvania governor; former Homeland Security secretary

Mitt Romney, former Massachusetts governor, 2012 nominee

Ileana Ros-Lehtinen, Florida congresswoman

Since the BBC posted its list last night, a few more high-level party people have come out, including former Secretary of State Condoleeza Rice, who posted the following at Facebook:

Another pretty stunning call for Trump to withdraw comes from Hugh Hewitt, the influential author, radio show host, and television analyst who has always been a faithful spear carrier for whomever the Republicans serve up:

For the benefit of the country, the party and his family, and for his own good, @realDonaldTrump should withdraw. More and worse oppo coming — Hugh Hewitt (@hughhewitt) October 8, 2016

That basically a third of the GOP Senate majority has reviled Trump is news of course, but it's not the end of the story. Where do Republicans who now refuse to vote for Trump turn in the ballot booth? Kelly Ayotte of New Hampshire has said, perhaps facetiously, that she will be writing in Trump's running mate, Mike Pence. Others have called for the party to elevate Pence or pull in another candidate, strategies that are untenable for all sorts of legal and logistical reasons. For his part, Trump has vowed that he will ever quit the race. Virtually all public denunciations of Trump have included almost equally sharp denunciations of Hillary Clinton, too.

While it's a stretch to expect elected Republicans to publicly endorse the ticket of a rival party, Libertarians Gary Johnson and Bill Weld are both former two-term Republican governors of blue-leaning states. At the very least, Johnson-Weld may be particularly attractive to "establishment" Republicans who tend to be more socially tolerant (in a GOP context, read pro-immigration and OK with marriage equality and possibly marijuana legalization). At the same time, Johnson-Weld also scratches the itch of Tea Party-style rank-and-file Republicans who are devoted to less spending and smaller government. No polls have been published yet that measure the early effects of the tape scandal yet, but prior to it, RealClearPolitics showed Clinton maintaining her lead and Johnson fading a bit in four-way national polls. At least that last part may change in the days ahead.