Balloons are placed into mesh netting before being hoisted to the rafters at the Wells Fargo Center on Friday in Philadelphia, before the Democratic National Convention kicks off. (Drew Angerer/Getty Images)

After Donald Trump presented a dark picture of the country at his convention in Cleveland last week, Hillary Clinton and the Democrats plan to project a more optimistic and inclusive vision of the future when they convene here starting Monday.

But the challenge for Clinton and her newly minted running mate, Sen. Timothy M. Kaine (Va.), will be to avoid becoming cheerleaders for the status quo and instead infuse that hopeful tone into an argument for change that could galvanize a frustrated and divided electorate.

Democrats promise four nights of speeches and entertainment that will highlight the core theme of Clinton’s campaign: “Stronger together.” The program will alternate among political heavyweights led by President Obama and former president Bill Clinton, celebrities such as Katy Perry and Lena Dunham, and everyday Americans whose aim will be to make Clinton appear more appealing and approachable.

Clinton’s advisers are confident that the Philadelphia festivities will present a far more united Democratic Party than Republicans were able to display at their convention, which was repeatedly marred by outbursts of dissent and division.

Central to that mission is the Monday night speech by Sen. Bernie Sanders (Vt.), who is charged with trying to rally his fervent supporters behind Clinton’s banner after a bruising primary battle, although there is lingering resistance to Clinton among some of his loyalists.

Who will speak in Philadelphia during the 2016 Democratic National Convention

The harsh tone of Trump’s convention — symbolized by the anti-Clinton chants of “Lock her up!” — gives the Democratic nominee-in-waiting and her allies an opportunity to expand her appeal to disaffected voters who are hungry for change but perhaps reluctant to embrace Trump and the brand of politics he enunciated in Cleveland. At the same time, the Democrats similarly risk overreach in their denunciations of Trump.

Another danger is that if protests outside the arena turn violent, it could mar the party’s effort to provide a united and relatively peaceful contrast to the Republican event.

“The Republicans painted a black canvas with maybe a little stripe of red, which would be Donald Trump’s tie,” Democratic pollster Peter Hart said. “Unexpectedly, the Democrats end up with a white canvas and a chance to paint it in any direction that they wish.”

All year, Clinton has struggled to find a message that both energizes the Democratic faithful and reaches to a different part of the general electorate disenchanted with politics as usual. This will be her challenge on Thursday night, when she becomes the first woman to accept the presidential nomination of a major party.

“If she is so concerned about the progressive revolt that days one, two, three and four [of the convention] are saying, ‘I’m Bernie Sanders Lite with pantsuits,’ then this whole group turned off by Trump has nowhere to go,” said Henry Olsen, a fellow at the Ethics and Public Policy Center.

But Housing Secretary Julián Castro, who was in the competition to become Clinton’s running mate, noted the importance of energizing the coalition that helped Obama win two elections.

“We need an infusion of motivation and energy to remind folks that we can’t take this election for granted,” he said. “The nature of modern presidential elections, given the country’s partisanship, is that these are close elections. It’s probably not going to be a blowout, and people need to understand how important their individual vote is.”

Four days of programming at the Wells Fargo Center will showcase the Democratic Party’s diversity and progressivism, designed to help as many voters as possible identify with Clinton and the rest of the ticket. The speakers will be white, black, Latino and Asian; Christian, Jewish and Muslim; old and young; gay and straight; male and female. There is expected to be a heavy focus on issues such as immigration, gay rights and gun control.

Having watched the Republicans fight among themselves in Cleveland, Democrats will arrive in Philadelphia full of confidence. But some in the party suggest that, like much about Trump over the past year, what looks to be a problem for him does not always become one.

“We need to be agnostic on just how negative its consequences will be or indeed whether they’ll be negative at all,” said William Galston, domestic policy adviser in Bill Clinton’s White House and now a senior fellow at the Brookings Institution.

Galston added, “The idea that Donald Trump’s convention speech allows Democrats to put any product they want on the shelf and expect the consumers to buy it is an optimistic proposition that I can’t embrace, and I hope the Clinton campaign won’t either.”

Democratic leaders have no doubt that their convention will contrast sharply with that of the Republicans.

“We just saw four days of some of the angriest people possibly in the United States of America — chaos, vitriol, confusion, plagiarism, mismanagement of a convention the likes of which we’ve not seen in either party in modern times,” said former Philadelphia mayor Michael Nutter (D).

Clinton enters her convention with a majority of Americans questioning her honesty. She has an opportunity to speak to a huge audience beyond the delegates assembled at the Wells Fargo Center, but many of those voters will be looking on skeptically.

Whit Ayres, a Republican pollster, noted that the underlying mood in the country puts Clinton at some risk as she campaigns to extend the Democrats’ hold on the White House to a third consecutive term.

“What Clinton cannot do is get herself in the position of defending the status quo, and that’s going to be a challenge, because she is the essence of the status quo,” Ayres said. “If she lets this [election] get defined as change versus status quo, where Trump’s change and she is not, that’s one way she can lose this thing.”

Trump’s coalition potentially cuts across traditional party lines, and as a political outsider, he has shown a particular ability to attract support from what he called “forgotten” Americans, many of them white and working class. “People who work hard but no longer have a voice: I am your voice,” Trump said in Cleveland.

Olsen suggested that Clinton could peel away some of that support with the right message aimed at the right segment of Trump’s base — such as white, working-class women. He said Trump’s daughter, Ivanka, set him up to talk to these women with her introductory speech but that the candidate failed to do so.

On Friday in Tampa, Clinton previewed how she would rebut Trump’s declarations, including his suggestion that he alone could fix what ails the country. “I can’t really imagine him on a white horse,” she quipped.

Clinton said: “We will offer a very different vision. It’s about building bridges, not walls, between people. It’s about making the economy work for everyone, not just those at the top. It’s about embracing our diversity that does make our country great.”

The convention’s nightly themes focus on unity. Opening night, Monday, will be “United together: Putting families first” and feature addresses by first lady Michelle Obama and Sanders, as well as Astrid Silva from Nevada, a “dreamer” brought to the United States as a child by parents who are illegal immigrants.

Tuesday’s theme is “A lifetime of fighting for children and families” and will be headlined by Bill Clinton and “the mothers of the movement,” whose sons and daughters were killed in police and other shootings.

Wednesday night, “Working together,” will star Kaine, President Obama and Vice President Biden. Many Democrats expect that Obama will reprise the role Bill Clinton played at the 2012 convention in Charlotte by delivering not only a full-throated endorsement of onetime rival Hillary Clinton, but also a point-by-point defense of his record and the economic gains under Democratic leadership.

On Friday, Obama gave a taste of how he would respond to Trump’s dark portrayal of the state of the country. “This idea that America is somehow on the verge of collapse, this vision of violence and chaos everywhere, doesn’t really jibe with the experience of most people,” he said. “I hope people, the next morning, walked outside, and birds were chirping, and the sun was out.”

The convention will reach its crescendo on Thursday night with the theme “Stronger together,” when Clinton will give her acceptance speech and be introduced by her daughter, Chelsea.

Clinton spokesman Glen Caplin said: “This convention will crystallize the fight that she’s already fought and what she will do going forward for American families as president. Hillary Clinton and Democrats will effectively make the case over these four days for an America that’s at its best when we work together to solve our problems.”

Democrats thought the Republican convention focused too much on Trump’s personality and offered generalities but few policy proposals to back them up — especially on the economy and jobs.

In Philadelphia, Democrats are expected to remind voters that the economy was roaring during Bill Clinton’s presidency and has improved considerably during Obama’s. Yet they also will acknowledge that there is more to do.

“There is an opening for someone who can create some hope that she knows how to make things better with some specific ideas,” said Ayres, the Republican pollster.

Striking the right tone on the state of the country, and the proper balance between a celebration of the Democratic base and an appeal for broader unity, remain the biggest tests for Clinton.

“I don’t think the American public desires to have ‘Happy days are here again,’ ” Democratic pollster Hart said. “The ability to condense the Clinton message into something which is both hopeful and realistic would make a huge difference.”