Vice President Harris has had a three-week launch to her campaign that most candidates can only dream of. Democratic enthusiasm is off the charts, money is flowing in, and volunteers are flocking to sign up to help get out the vote ahead of Nov. 5.

But campaign veterans say this honeymoon — like those that came before it — will end. They always do.

“There’s definitely a new energy that’s there. It’s just a question of, will that energy still be there after Labor Day?” said Andra Gillespie, a political scientist at Emory University.

Harris has yet to lay out a lot of detailed policies, sit down for a tough media interview, or debate her Republican opponent, former President Donald Trump.

And to this point, Trump and his campaign have struggled to figure out attacks on Harris that will stick. “So far they’ve been easy, because they’ve been disjointed or outrageous, but she’s going to have to prepare for an attack that lands,” Gillespie said.

Clinton 2016: a campaign that didn’t have a honeymoon

No one expected Harris would have it this easy, said Robby Mook, who ran Hillary Clinton’s 2016 campaign.

Mook said Harris stepped into the role so late in the game that there’s still a novelty to her candidacy — and she escaped having to go through a bruising 18-month primary.

“When you launch a campaign, normally you’re expected to kind of have everything on day one,” Mook said, explaining Harris has been given unusual latitude because of the unusual way she was nominated. Her campaign website still doesn’t have a policy page, for instance.

“All that said, at some point she’s gonna sit down and have interviews and get hard questions. The campaign is gonna make a mistake. These things happen,” he said.

The Clinton campaign arguably never had a honeymoon. “We had to make clear to the team right away that this was just gonna be really hard. It’s hard to win. It was going to be hard to elect the first woman president. It was going to be hard to get a third term for Democrats in the White House,” Mook recalled.

Harris bypassed a challenge that many women face in politics

Harris is now running to be the first female president — but she was able to bypass one of the biggest challenges female candidates face, said Amanda Hunter, with the non-partisan group Gender on the Ballot.

“Women are often punished when they are perceived to be showing ambition in politics,” Hunter said. But in Harris’ case, she stood by Biden right up until he stepped aside and endorsed her, which Hunter said changed the way that voters perceive her.

“She was taking on this position in an almost service role and was not showing ambition herself. And that is one reason that voters may have a different reaction than if it were a woman stepping up and saying, ‘I want to run for president,’” Hunter said.

Harris campaign says it is not taking anything for granted

Harris inherited a campaign team made tough and resilient for having survived a grueling month where their candidate, President Biden, was effectively pushed out by his own party.

“Think of what this campaign just went through in the last month,” Mook said. “When they have a bad day or two or three, or or a bad week, that’s not going to feel like anything they haven’t felt before.”

A Harris campaign spokesman said the team is taking nothing for granted. “We believe this will be a very close election, decided by a very small number of voters, in just a few states,” said Kevin Munoz.

“That means wasting no time, and instead, using the recent momentum to relentlessly make our case to the hard to reach voters who have not made up their mind yet,” Munoz said.

For her part, Harris has been trying to prepare her currently ecstatic supporters for a time when it won’t be so fun.

“Listen, we also need to level-set,” she told cheering crowds at a rally in Philadelphia. “We are the underdogs in this race, but we have the momentum and I know exactly what we are up against.”

Romney 2012: a campaign where the honeymoon ended

When Republican presidential candidate Mitt Romney trounced a sluggish then-President Barack Obama in their first debate in 2012, there was a moment where the Romney campaign felt like they were winning.

“You talk to many people the day after — you would’ve thought that we were the odds-on favorite to win that race,” said Kevin Madden, an adviser to Romney’s campaign.

But that honeymoon didn’t last long. “Within two weeks, the race was right back to where the fundamentals had it, which was an advantage to the incumbent,” he said.

In the 2024 campaign, Madden says the fundamentals point to a close race – leaving no room for error.

And Madden cautioned there could still be headwinds that no one can predict, such as another bad economic report or maybe a natural disaster.

In 2012, that was Superstorm Sandy, which walloped the East Coast and gave Obama the opportunity to demonstrate leadership in a crisis. Madden said he has no doubt that hurt Romney.

“When you asked [voters] was the Obama administration response to Hurricane Sandy viewed positively, and did it factor in their vote — it did,” he said.

NPR’s Alejandra Marquez Janse and Jordan-Marie Smith contributed to this story.