Democrats, both elected and rank-and-file, exhaled sighs of relief on Sunday afternoon, believing their hopes of defeating former President Donald Trumps political comeback had earned an improbable second life.

President Joe Bidens decision not to run for a second term , combined with the partys quick but not yet fully definite coalescing around Vice President Kamala Harris, has injected new life into a campaign sapped of both financial and emotional energy by the 81-year-old incumbents disastrous debate performance last month in Atlanta.

Republicans apparent frustration at the coming candidate swap only added to Democrats excitement, convincing many that moving on from Biden to Harris was the right move for the party.

Trump had opened up significant leads over Biden in almost all major swing-state polling, as traditional Democratic constituencies expressed concerns over Bidens ability to serve another four years in office. The likely switch to Harris, Democratic officials believe, gives the party a chance to reset the race, reframing it as a battle between a younger and more dynamic prosecutor and a 78-year-old man with dozens of felony convictions.

We now have a great way to contrast between people who want to turn the door on the politics of the past, Colorado Gov. Jared Polis (D), who signaled his ultra-fast endorsement of Harris by sending out a social media message with coconut and palm tree emojis , said Sunday on CNN. Trump was almost 80 years old. We have the vigor, we have the energy on our side, and I couldnt be more excited. (The emojis are a reference to a 2023 Harris speech where she recounted something her mother would tell her and her sisters: You think you just fell out of a coconut tree? You exist in the context of all in which you live and what came before you. The speech went viral on TikTok earlier this year.)

The party is still facing significant headwinds, and Trump remains favored to win in November. Harris is tied to Bidens unpopular administration, and voters have punished incumbent parties of all ideological stripes around the world over high inflation and general malaise following the COVID-19 pandemic. Republicans are clearly eager to attack Harris, over both her role on immigration policy under Biden and left-leaning positions she took during the 2020 presidential primaries.

Its also not absolutely certain Harris will become the nominee. Marianne Williamson, a Democratic primary candidate in 2020 and 2024, has said she will wage a long-shot bid to topple Harris, and Sen. Joe Manchin (I-W.Va.) is considering rejoining the Democratic Party to challenge Harris.

Still, with leading Democrats like former House Speaker Nancy Pelosi (Calif.) and Senate Majority Leader Chuck Schumer (N.Y.) believing Bidens chances of defeating Trump and his authoritarian agenda were essentially nil, his departure from the race is giving many in the party a reason to believe.

Relief and hope, one Democratic operative said, requesting anonymity to frankly describe the partys mood.

Now, party officials said, they are hoping those emotions translate quickly into volunteer energy and financial donations. (Bidens fundraising had fallen off a cliff since the debate, with many big-money donors refusing to contribute to the party until he dropped out.)

You are seeing people uniting for her candidacy and you already have infrastructure set up in all of these swing states and across the country, Sen. Amy Klobuchar (D-Minn.) said on CNN. What I think this is going to add is just a lot of energy. Youre going to have a new ticket, youre going to have volunteers showing up, they know the stakes are high, and sometimes a short-term campaign gets people going more than a long-term campaign.

ActBlue, the online fundraising platform used by almost every Democratic campaign, said small-dollar donors were responding to Harris elevation with enthusiasm, and had contributed over $50 million as of 9:30 p.m. only the second time in history they had surpassed that mark.

Harris is set to inherit Bidens campaign staff and funds. On a conference call with staffers Sunday afternoon, top campaign officials indicated that staffers would keep their jobs, though other Democrats said they expect Harris to bring in at least a handful of new people.

All of you, all of us, wherever we come from, are here for Joe Biden and Kamala Harris and to defeat Donald Trump, campaign chair Jennifer OMalley Dillon said on the call, according to a campaign staffer who was not authorized to speak publicly. And while today is a big day of transition, nothing changes with why you got here and what were all here to do. But the path forward is a path that is for all of us to do this together. So let me tell you what I know to be certain, which is that every single person here whatever your job, whatever youre doing you have a job. You have a home.

In a statement, Harris said she plans to quickly start campaigning across the country. Over the past year, I have traveled across the country, talking with Americans about the clear choice in this momentous election. And that is what I will continue to do in the days and weeks ahead, she said. We have 107 days until Election Day. Together, we will fight. And together, we will win.

Harris optimism is driven by some polling indicating she performs better than Biden with young voters and Black and Latino voters. Large number of those voters have so far appeared in danger of staying home, voting third party or even flipping to support Trump. Democrats were confident Harris could win them over.

If you go online, shes been the topic of a lot of young people on TikTok and online and a lot of people that I think are really excited by her. Weve got to work on translating that into people going out and voting, and I think shell be able to do that, Rep. Maxwell Frost (D-Fla.), at 27 the youngest member of Congress, said on a Zoom call with reporters. Were seeing a lot of coconut emojis, which I guess people are associating with the vice president, or whatever. Gen Z can find weird ways to sort of uplift someone, and I think were seeing that a lot.

The excitement was not universal. A handful of hardcore Biden loyalists in Congress bemoaned the incumbents exit, arguing hed been unfairly boxed out of the race.

I hope the geniuses that pushed the most consequential President of our lifetime out, have a plan, Rep. Jasmine Crockett (D-Texas) wrote on social media , even as she endorsed Harris in the same post.

Trump and other Republicans, meanwhile, seemed to be fuming they could no longer face Biden. In a series of posts on Truth Social, Trump first demanded that the September presidential debate, scheduled to appear on ABC, instead be switched to the distinctly more Trump-friendly Fox News. He then suggested the GOP should be reimbursed for the money it has spent running against Biden.

Shouldnt the Republican Party be reimbursed for fraud in that everybody around Joe, including his doctors and the Fake News Media, knew he was not capable of running for, or being, President? Trump wrote . Just askin?