Supporters of Sen. Bernie Sanders chanted his name throughout the first day of the Democratic National Convention, frequently interrupting speeches. From first lady Michelle Obama's moving speech to many politicians slamming Donald Trump, here's what happened. (Nicki DeMarco/The Washington Post)

Democrats began their presidential nominating convention Monday with a struggle to fully unite behind Hillary Clinton, following a dramatic day of intraparty squabbling and protests.

But by the end of the evening — after back-to-back-to-back speeches by first lady Michelle Obama, Sen. Elizabeth Warren (Mass.) and Sen. Bernie Sanders — the party began to focus more on defeating Republican nominee Donald Trump than on fighting among themselves.

Sanders, whose “political revolution” had electrified millions of Democrats throughout his hard-fought primary campaign with Clinton, was greeted by several minutes of sustained applause as he took the stage to cap the night. He repeatedly thanked the crowd before he was finally able to begin his remarks.

“Election days come and go,” he said, before referencing his revolution on behalf of the poor and marginalized. “That struggle continues.”

Sanders didn’t mention Clinton’s name for several minutes, but when he did, he endorsed her candidacy and brought the crowd to its feet.

“We need leadership in this country which will improve the lives of working families, the children, the elderly, the sick and the poor,” he said. “We need leadership which brings our people together and makes us stronger — not leadership which insults Latinos, Muslims, women, African Americans and veterans — and divides us up.

“By these measures, any objective observer will conclude that, based on her ideas and her leadership, Hillary Clinton must become the next president of the United States. The choice is not even close.”

It was a stark contrast from the early part of the program. Before Sanders took the stage at Wells Fargo Center, mentions of Clinton’s name had been met with a smattering of boos in a speaking program that began under a cloud of controversy after a leak of internal emails showed party strategists appearing to plot against Sanders during the primary campaign. Sanders supporters chanted his name repeatedly through the night, shouting over mentions of Clinton.

Sanders’s speech capped an evening with a lineup heavy on liberal voices, including that of Warren, a hero to the left who had been a favorite to challenge Clinton.

The program was intended to be a grace note to Sanders and the improbable strength and longevity of the insurgent challenge he mounted against the longtime front-runner. Warren thanked Sanders at the start of her keynote remarks, to loud applause.

“For me, this choice is personal,” said Warren, who was considered as a vice-presidential running mate. “It’s about who we are as people, it’s about what kind of country we want to be.”

Warren lambasted Trump for “fanning the flames of fear and hatred” during an address in which she compared his electoral strategy of “divide and conquer” to tactics that kept the South racially segregated during the Jim Crow era.

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Warren has emerged as one of Trump’s fiercest critics, and her blistering speech Monday night seemed to enhance that reputation.

Warren warned that Trump is “a man who must never be president of the United States.”

The first lady also drew a strong reaction from the crowd. Her voice grew thin as she said that, because of Clinton, her teenage daughters do not question that a woman can be president.

“Hillary Clinton has never quit on anything in her life,” Obama said to cheers.

“We don’t turn against each other — no, we listen to each other,” she said, before invoking two of Clinton’s signature mottos. “We are always stronger together. I am here tonight because I know that that is the kind of president that Hillary Clinton will be — and that’s why in this election, I’m with her.”

The program featured Trump in absentia, in video highlight reels of controversial statements he has made. Democrats used Trump’s past insults to tee up speakers representing some of the most offended groups, including women, the disabled and immigrants.

Trump was watching the turmoil and the convention speeches, and needled Clinton, Warren and Sanders via Twitter.

“Bernie Sanders totally sold out to Crooked Hillary Clinton. All of that work, energy and money, and nothing to show for it! Waste of time,” he wrote.

The policy fights that underlie the Clinton-Sanders primary fight remained on display Monday, including trade deals, climate change and fracking, a particularly strong issue in Pennsylvania.

The Democrats approved a party platform Monday that reflects the influence of the liberal ideas Sanders advanced. Clinton, however, remains opposed to breaking up the country’s largest financial institutions and making government-paid health care a universal right.

“This is your victory, too,” Clinton campaign chairman John Podesta told Sanders supporters to polite applause.

Democrats were hoping to showcase a smooth, error-free convention that would contrast sharply with last week’s Republican gathering in Cleveland, which was marred by plagiarism and intraparty skirmishes.

The opening day focused on Clinton’s background in helping children and families, and featured a parade of elected officials, union leaders and others praising her commitment to immigration reform, gay rights, addiction treatment and other issues.

“She’s been paying it forward her whole life,” Sen. Cory Booker (N.J.) told the crowd.

Booker, a rising star in the party who was considered as a vice-presidential running mate, led the arena in chants of “We will rise” and laced into Trump.

“We cannot be seduced by cynicism in our politics,” he said. “We will not surrender the moral high ground,” he added. “Here in America, love trumps hate,” he shouted, to some of the loudest applause of the night.

One of the evening’s more awkward moments came when comedian Sarah Silverman, a prominent Sanders supporter during the primaries, took the stage with Sen. Al Franken (Minn.), a fellow “Saturday Night Live” alumnus who backed Clinton early.

“This past year, I’ve been feeling the Bern,” Silverman said.

The Berniecrats cheered.

“Relax, I put some cream on it,” she added, before explaining why she will vote for Clinton “with gusto.”

At that, Sanders supporters began to boo loudly. There were rival chants of “Ber-nie” and “Hill-a-ry” as Franken and Silverman exchanged glances.

Then Silverman went off the teleprompter.

“Can I just say to the Bernie or Bust people,” she said, “you’re being ridiculous!”

The Clintonites in the crowd loved the unscripted rawness of the moment, and their roar overtook the Sanders backers.

Later in the week, the party stalwarts will hear from President Obama, Vice President Biden and former president Bill Clinton, among others. The convention will culminate Thursday in a speech from Hillary Clinton, who is poised to make history as the first woman to be nominated for president by a major party.

Outgoing Democratic National Committee Chairman Debbie Wasserman Schultz (Fla.) stayed offstage following heavy criticism over the leak of a trove of embarrassing DNC emails.

Baltimore Mayor Stephanie Rawlings-Blake stepped in for Wasserman Schultz to formally open the convention about 4:15 p.m.

Wasserman Schultz excused herself from the exercise earlier in the day, bowing to heavy opposition from party activists to try to ease hard feelings.

The decision was one of many dramatic developments during a day of discord that included threats of a revolt on the convention floor by Sanders delegates and loud protests by his supporters at the gates to Wells Fargo Center, where the convention is being held.

The FBI said it is investigating the email breach that triggered much of the intraparty friction, and the DNC’s incoming temporary chairwoman, longtime Democratic adviser Donna Brazile, and others issued a public apology for hacked emails that showed DNC staff members apparently scheming to help Clinton win the Democratic primaries.

The emails cost Wasserman Schultz her post. Under heavy pressure from the Clinton campaign, she agreed Sunday to step aside when the four-day convention closes Thursday.

Earlier Monday, Sanders was cheered by supporters at a swan-song rally that reprised many of the democratic socialist’s signature lines. He had trouble quieting supporters who booed mentions of Clinton and her running mate, Sen. Timothy M. Kaine (Va.).

“We have got to elect Hillary Clinton and Tim Kaine!” he told the crowd.

Sustained boos and shouting followed, as Sanders stood at the lectern, hand in the air. He was unable to continue for several long moments but then spoke over the crowd — not to praise Clinton but to denounce Trump.

“Brothers and sisters, this is the world we live in!” he shouted.

“Trump is a bully and a demagogue. Trump has made bigotry and hatred the cornerstone of his campaign.”

As Sanders went on, listing groups Trump had “insulted,” the crowd gradually quieted.

According to a Democratic Party official familiar with the talks, the Sanders team reached out to the Clinton team Monday afternoon to voice concern about potential disruptions during the evening speeches.

Sanders sent a signed text message to some supporters late in the afternoon, pleading for calm.

“I ask you as a personal courtesy to me to not engage in any kind of protest on the floor. It’s of utmost importance you explain this to your delegations — Bernie,” the message read.

Volunteers from the Sanders campaign were trying to pressure convention organizers to take roll-call votes on the presidential and vice-presidential nominations, which would stretch out the process and highlight pockets of disagreement.

The Clinton campaign said she welcomes a 50-state roll-call vote on the nomination.

The email messages released by hackers were posted Friday on the website WikiLeaks. They undercut claims by the party and the Clinton campaign that the process was open and fair for Sanders.

The emails revealed a DNC official apparently discussing how to use Sanders’s religion against him to help Clinton before the Kentucky and West Virginia primaries. In another email, a Clinton campaign lawyer told the DNC how it could respond to claims from the Sanders campaign that it was improperly using a joint fundraising committee with state parties.

The Washington Post reported last month that Russian government hackers penetrated the DNC, stealing opposition research about Trump and compromising the party’s email and chat systems.

The Clinton campaign — and several cybersecurity experts — said the leak was a political ploy carried out by the Russian government to help Trump’s campaign.

Clinton campaign manager Robby Mook said the DNC is reviewing its internal emails to determine what damaging correspondence might be in the hands of Russian hackers.

Republicans, led by Trump, seized on the episode.

“So Debbie was totally loyal to Hillary. And Hillary threw her under a bus. And it didn’t take her more than five minutes to make that decision,” Trump said during a campaign event in Roanoke.

A pair of new polls released Monday showed a competitive race heading into the convention. A CNN/ORC survey conducted after the GOP gathering showed Trump jumping ahead of Clinton. A CBS News poll showed that the contest is effectively tied.