Kamala Harris took the stage at the Democratic National Convention on Thursday night and told Americans they had a “precious, fleeting opportunity” to support her candidacy and make the extraordinary times since Donald Trump entered the political arena nine years ago a thing of the past.

Although her 40-minute speech did not quite match the Obamas’ outstanding rhetoric at the beginning of the week, the euphoria and confidence in the arena were clearly palpable.

With the support of influential celebrities and widespread sentiment among Democrats that they are turning over a new leaf, enthusiasm among party supporters has not been this high since Barack Obama’s first presidential campaign in 2008.

The exuberant mood among the delegates in Chicago is due, on the one hand, to the relief of not having to run against Joe Biden in this election, a candidate whose advanced age was a major burden, and, on the other hand, to the joy at how smoothly Harris and her running mate Tim Walz have taken their places at the top of the electoral list.

But behind the scenes, party strategists worry that Democratic voters and activists – who will have to take to the streets, knock on doors and convince their friends and families to go to the polls on November 5 – could get carried away.

Polls have shifted in her direction in the weeks since President Biden stepped down, but it’s still a very close race, with a handful of states – Georgia, Arizona, Nevada, Wisconsin, Pennsylvania, Michigan and North Carolina – also up for grabs.

In almost every constituency, either candidate appears to be within reach of victory, and if the last six weeks are any indication, the political dynamics could change quickly in the remaining 70 days.

Jim Messina, a veteran Democratic strategist who ran Barack Obama’s 2012 election campaign, told the BBC podcast Americast that any certainty that the Democrats would win was misplaced.

“Kamala Harris has had the best 30 days in American politics that I’ve seen in a long time since she entered this race,” he said. “But she’s still tied (in the polls). The Democrats have fought their way from a five-point deficit to a tie. So it’s still a close race with 75 days to go.”

Although the mood here reached its peak last night, the neck-and-neck race shows that the Democrats still have a lot of work to do if they want to be sure of the White House.

Trump seems to be struggling to figure out how to campaign against Harris. He doesn’t seem to know what line of attack to take and hasn’t even settled on one of his usual nicknames.

One prominent Democratic strategist told me he believes Trump will soon figure out how to define Ms. Harris in a way that best serves his campaign, because that is his great political skill. And if he succeeds, this election will be that much more difficult for Harris.

Despite all the enthusiasm and confidence that emanated from the stage of the party conference, there were also warnings.

In her speech on Tuesday night, Michelle Obama warned that the election would be extremely close. “We must cast enough votes to remove any doubt,” she told the crowd. “We must destroy any attempt to suppress us.”

Her husband, Barack Obama, followed up with a similar call in a one-two punch designed to motivate the thousands in the arena to take to the streets across the country when they returned to their hometowns.

“It’s up to all of us to fight for the America we believe in,” the former president said. “And make no mistake, it’s going to be a fight.”

The candidates in the crucial swing states that will decide the outcome of this election know only too well how much work lies ahead of them.

“I’ve been telling Democrats everywhere I go this week, ‘Don’t get high on your own stash and don’t think everyone is as high-energy as you,'” Democratic Rep. Elissa Slotkin, who is running a close Senate race in Michigan, told Politico.

At the convention, delegates, visibly buoyed by the events of the week, seemed to have taken Obama’s message to heart.

Cameron Landin, a 21-year-old from Georgia, a key swing state in the South that Democrats won for the first time in 28 years in the last election, said he knew victory was not a given.

“I really believe Kamala Harris is going to win,” he said a few hours before Harris took the stage. “But that doesn’t mean I’m not nervous.”

The regional organizer from the city of Savannah said people like him are focused on one thing: increasing voter turnout.

“That means people are working 60-plus hours a week, seven days a week in the organization. That means volunteers are going out – making phone canvasses, calling voters, canvassing for votes.”

“That’s what will bring us victory,” he said, pointing to the crowd of delegates waving signs for Harris and Walz. “The people on the ground.”

Nevada Democratic Rep. Susie Lee, whose district includes part of Las Vegas, said she had no illusions that the election would be extremely competitive, especially in her swing state.

“It’s far from a done deal,” she said. In some Nevada districts, she explained, as few as 50 to 100 votes could make the difference. “We obviously need to get people involved and go to the polls.”

“But I’ll tell you – I think people are fed up with Donald Trump,” the congresswoman said. “There’s a clear choice between Harris and Trump. I think people see that.”

Millions of voters followed the Democrats’ political festival in Chicago – more than 20 million viewers tuned in on each of the first three evenings.

The Harris-Walz team will almost certainly see another upswing in the opinion polls after this week. But that is to be expected after every party conference.

The question will be whether the momentum they are riding will continue, especially now that the country is learning more about Harris, who has so far avoided difficult media interviews and revealed few details about her policies.

Trump has almost half the country under his control. And they know him well after three consecutive presidential campaigns.

The Democrats could well win this election, but they will have a lot of work ahead of them.

Additional reporting by Bernd Debusmann Jr.