MIAMI — Ten of the Democrats running for president railed against what they see as a deeply imbalanced economy and President Donald Trump’s immigration policies in the first debate of the 2020 presidential campaign Wednesday night, while clashing on how to expand health coverage.

Massachusetts Sen. Elizabeth Warren, whose proposals aim to reshape the economy, break up big corporations, and more equally distribute wealth, shaped the opening minutes of the first direct confrontation in the sprawling nominating contest.

“Who is this economy really working for? It’s doing great for a thinner and thinner slice at the top,” Warren said early in the debate. “When you’ve got a government, when you’ve got an economy, that’s doing great for those with money and isn’t doing great for everyone else, that’s corruption pure and simple. We need to call it out, we need to attack it head on, and we need to make structural change.”

Competitors joining her at the Adrienne Arsht Center for the Performing Arts followed with similar denunciations, even those who have staked out more moderate positions.

“We know not everyone is sharing in this prosperity, and Donald Trump just sits in the White House and gloats about what’s going on," said Minnesota Sen. Amy Klobuchar, who pitched her plan to make community college free and increase Pell grants.

The attacks on inequity hinted at how Democrats plan to argue for a change in the White House despite strong economic statistics and job gains, and showed how the president’s populist appeals have spread throughout the political system. Polls suggest that majorities approve of how Trump is handling the economy even as many disapprove of the president himself, making that issue one of his strongest reelection selling points.

Warren arrived as the candidate with the most momentum and political stature among the candidates on stage Wednesday night, after a random drawing scheduled the other top-five contenders — former Vice President Joe Biden, Vermont Sen. Bernie Sanders (Ind.), California Sen. Kamala Harris, and South Bend (Ind.) Mayor Pete Buttigieg — among the 10 to be on stage Thursday, out of 25 announced candidates in all.

She and her policies dominated the early stages of the event, though she faded as the debate went on and several candidates at the back of the pack seized opportunities to raise their profiles.

For the most part, the candidates did not directly attack Trump, but the president weighed in, tweeting “BORING!” and criticizing technical glitches that marred the national broadcast.

Biden, the leading Democratic candidate, was also barely mentioned.

Some of the sharpest early exchanges came when the Democrats were asked whether they favored a health-care plan that would eliminate private health insurance in favor of government-run coverage for all.

Only Warren and New York Mayor Bill DeBlasio supported abolishing private insurance. Several others said they wanted government insurance as an option.

“Look at the business model of an insurance company. It’s to bring in as many dollars as they can in premiums, and pay out as few dollars as they can for your families,” Warren said.

“We should be the party that keeps what’s working and fixes what’s broken,” countered John Delaney, a former congressman from Maryland who has gained little traction so far. “Why do we have to stand for taking away something from people?”

New Jersey Sen. Cory Booker argued that he favors the “Medicare for All” plan backed by Sanders and Warren, but hinted that he doesn’t see it as an immediately achievable solution.

“We have to do the things immediately that are going to provide better care,” Booker said.

Some of the most emotional moments came when the moderators, from NBC and MSNBC, brought up undocumented immigration and the photo seen this week of a migrant father and his daughter lying dead, face down, in the Rio Grande.

“It’s heartbreaking, and it should also piss us all off,” said Julián Castro, a Texan and former secretary of housing and urban development under President Barack Obama.

He led the way on the debate on one of the most controversial topics of the moment, saying he would sign an executive order to do away with Trump’s zero tolerance policies and would work to repeal the law that makes unauthorized immigration a crime. That, he said, would prevent the family separations seen under Trump. Instead, illegal entry would be treated as a civil offense.

The two debates have been widely anticipated as the first major inflection point in the primary campaign, giving a national audience a first chance to see the contrasting Democratic messages, policies, and personalities side by side.

With many of the heavyweight names out of the picture for a night, Wednesday’s debate gave several candidates an opening to jump-start their campaigns. Booker, Klobuchar, and former Rep. Beto O’Rourke of Texas were all near center stage alongside Warren after months of hovering in the shadows of those leading the pack.

Several tried to emphasize their backgrounds, introducing themselves while also talking policy.

Booker, O’Rourke, and Castro all slipped into Spanish. Hawaii Rep. Tulsi Gabbard emphasized her military service in Iraq.

Booker frequently talked about his experience leading a low-income, largely minority city, Newark, N.J., and, by the Washington Post’s count, led the way in terms of speaking time for much of the night. He stressed his plan to require gun owners to obtain licenses and urged stronger protections for transgender people, particularly African Americans. “We need to have a president who will fight to protect LGBTQ Americans every day,” he said.

Several others also tried to make a splash. Castro pointedly challenged fellow Texan O’Rourke on his immigration expertise. DeBlasio, stuck at the edge of the row of lecterns, sharply interjected and argued for a bolder vision from his party.

“This Democratic Party has to be strong and bold and progressive, and in New York we’ve proven that we can do something different,” DeBlasio said. “There’s plenty of money in this country, it’s just in the wrong hands.”

Washington Gov. Jay Inslee, who has centered his campaign on the issue of climate change, touted the environmental plans in his state as “the gold standard.”

“We are the first generation to feel the sting of climate change, and the last generation with a chance to do something about it,” Inslee said.

They and Ohio Rep. Tim Ryan were getting a rare moment of national exposure as they tried to move from the fringes of the campaign.

A second pair of debates is scheduled for late July in Detroit, but lagging candidates are in danger of missing further debates beginning in September, when the polling and fund-raising thresholds increase.