Several Clinton allies said she will take the high road at the debate, seeing no need to go over the particulars of Trump's vulgar comments in detail and attempting to show her fitness for high office by contrast.
"How can you get in front of this story? You wouldn't want to if you could," said long-time Clinton ally James Carville.
Several Clinton aides dismissed the "made up talk" that Trump could be taken off the ballot, despite calls for him to step aside.
Campaign manager Robby Mook was assured by longtime Clinton election lawyer Marc Elias that it is too late for any change in the ballot, the aide said.
The Trump comments are unlikely to change any of the campaign's basic strategy with a month left before the election, the aide said.
That strategy is focused on seven battleground states and the various equations for victory among them, and at this point Clinton strategists do not see that map expanding because of the Trump comments, the aide said. The campaign also has no plans to shift resources now, the aide said.
Democrats, confident that Trump will remain on the ballot until Election Day, are growing increasingly optimistic about their Senate chances. And their position in the House could also improve, though there is still scepticism that they could retake a majority there.
"The reality of this race at this time is that this is an extinction-level event in a campaign," said one Democrat close to the Clinton campaign. "So it's not just something that will just be contained to Trump. It's an issue that will put a lot of seats in play."
Mook and Clinton campaign chairman John Podesta are also expected to address the comments and Trump's fitness for office on public affairs television programmes tomorrow.
Just how far the damage extends beyond Trump's candidacy remains to be seen. Democrats are glued to their Twitter feeds and inboxes, watching as a flood of Republicans move to abandon Trump.
So far, the Clinton campaign has sent text and email missives to supporters urging them to give money and register to vote. The campaign released a hastily put together web video featuring the new footage of Trump's lewd comments.
The comments about women offer Democratic candidates in national and state elections a way to put Republican opponents on the spot.
Clinton aides joined down-ballot candidates and operatives in applying unprecedented pressure on Republican candidates to disavow Trump and rescind their endorsements or risk being tied to him on Election Day.
"The play right now for the rest of the day and maybe tomorrow is for the campaign committees to make these guys pay the price and call them out while the Republican Party itself implodes," said Jim Manley, a former aide to Senate Minority Leader Harry Reid.
Clinton aides say it will take days to fully assess the damage - and potential opportunity - of Trump's latest controversy. Down-ballot candidates will have to wait until a day or two after the debate to see whether the Clinton campaign begins devoting more financial resources to competitive races.
The campaign is also keenly focused on early voting, which is already underway or beginning in a matter of days in such key states as Iowa, Ohio and North Carolina. The campaign had already planned to deploy ground troops and staffers in the coming weeks to push early voting in a number of states. The latest damaging revelations about Trump provides them with new ammunition.
The debate at Washington University in St Louis is also seen as a critical moment.
With Trump's support among Republicans eroding rapidly, and the GOP nominee rejecting calls for him to drop out, several Democrats said they believe he will come into the debate with the mind-set of a "wounded animal" - a factor that they say could make him more dangerous.
"I've never seen a candidate walk into a debate with this much at stake," Carville said. "He's overweight, he's old, he's tired and he's crabby. And he's going to have a very long hour and a half."
