DAVENPORT, Iowa — Four days ago, as scores of Republicans denounced Donald Trump over a leaked 2005 tape of him boasting about sexual assault, Sen. Tom Cotton (R-Ark.) issued an ultimatum.

"He needs to throw himself on the mercy of the American people," Cotton told Republicans at a fundraising dinner in Des Moines. “If he doesn’t . . . then he should step aside and allow the Republican Party to replace him with an elder statesman who will."

On Tuesday, after the second presidential debate and several more days of campaigning for local candidates, Cotton said that Trump had passed the test. In a radio interview with Arkansas's KARN and in a town hall meeting here, Cotton said Trump had apologized and could "change his ways" en route to winning the White House. In a news conference, he and Sen. Chuck Grassley (R-Iowa) reaffirmed their endorsements of Trump.

To the barely concealed delight of Democrats, Trump's aggressive debate performance has shored up Republican support despite a swoon in his overall polling. According to a new Wall Street Journal-NBC News poll, just 63 percent of Republican voters said in the wake of the tape's release that their party's other candidates should back Trump. After the debate — and after the high-profile Trump news conference with three women who years ago had accused Bill Clinton of sexual misconduct — that number rose to 83 percent.

Trump's debate apology was one of his weaker moments of the night. Gripping his microphone like a karaoke singer confronting an unfamiliar song, Trump insisted that his 2005 reminiscence about grabbing a woman to force himself on her was "locker-room talk," and he pivoted to the need to destroy the Islamic State.

For Cotton, and for the vast majority of Republicans who have not called for Trump to quit the race, it was enough. Asked whether anything else could get him to tell Trump to step aside, Cotton said he would not "speculate about future circumstances."

"As I said on Saturday, Donald Trump needed to apologize for his remarks, take responsibility for them and focus on trying to bring change to the country," the congressman said. "He may not have done that the way you or I would have done that, but he did it. He got back on issues that matter to Americans."

In other words, Cotton was no longer interested in the push to get Trump to quit the ticket, a fantastical scenario floated by plenty of worried conservatives. Sen. Mike Lee (R-Utah), who had never endorsed Trump — and fought his nomination through the Republican convention — was the most prominent member of Congress to press the idea, and he was joined by several swing-state and swing-district Republicans.

But with each passing day, as early ballots are cast and the window for an emergency Republican National Committee meeting narrows, the dump-Trump campaign becomes less of a hope and more of a talking point. Democrats, who believe that most Republicans missed their better, earlier chances to un-endorse Trump, are hopeful that more damaging stories about the GOP nominee could emerge before the election, based on the hours of hot-mic audio he has recorded.

Republicans instead are trying to pivot, buoyed by a Trump debate performance that has improved his standing with the GOP base while leaving him in his worst polling shape since the summer. In Davenport, after an audience question and several more questions from reporters about his position on Trump, Grassley asked whether reporters spent this much time harassing Democrats about Clinton.

"I hope that they're asking Democratic candidates what they think of Hillary Clinton lying, covering up emails, not [being honest to] the Benghazi people at the ceremony at Dover Air Force Base," Grassley said. "Those seem to be things they should be asked regularly."

Indiana Gov. Mike Pence (R), Trump's running mate, used his own Monday appearance in Iowa to ask why the mainstream media was not spending more time on revelations from hacked Clinton campaign emails released by WikiLeaks — emails that have revealed embarrassing chatter about campaign strategy.

"I’m sure it’ll be the seventh or eighth item on the evening news tonight," Pence,  who was the focus of bogus Saturday and Sunday rumors that he would quit the ticket, snarked at a rally in Newton.

Pence, Cotton and Grassley will appear later Tuesday at a Republican fundraising dinner in Bettendorf.