An uneasy détente after drama on DNC’s opening day. Will it last?

Sen. Bernie Sanders, I-Vt., waves to supporters during the first day of the Democratic National Convention in Philadelphia. (Photo: Mark J. Terrill/AP Photo)

PHILADELPHIA — In back-to-back speeches Monday, America’s two most popular progressives — Massachusetts Sen. Elizabeth Warren and Vermont Sen. Bernie Sanders — tried to unite the Democratic Party around the presumptive nominee, former Secretary of State Hillary Clinton, after a rancorous, decorum-shattering session that saw delegates loyal to Sanders booing or chanting “Bernie! Bernie!” nearly every time Clinton’s name was mentioned.

By evening’s end, Warren and Sanders seemed to have succeeded, at least for the moment, in their mission. (Michelle Obama’s rapturously received address — a mother-in-chief’s case for Clinton — didn’t hurt, either.) The Bernie or Bust holdouts were no longer the loudest voices in the Wells Fargo Center. “Hillary Clinton” was now an applause line. The boos were reserved for Donald Trump.

The question now is whether the delicate détente negotiated Monday night will hold for the rest of the week — or whether the divisions on display throughout the day will erupt yet again, disrupting the message of party unity that the Clinton campaign was hoping to convey in the City of Brotherly Love.

Warren was first. She framed the election as a choice between “a man who inherited a fortune from his father” — a man “who only cares for himself, all day, every day” — and “one of the smartest, toughest, most tenacious people on this planet.”

“I’m with Hillary,” Warren said.

A few disillusioned delegates shouted, “We trusted you!” But the rest of the arena roared.

Then came the headliner. As Minnesota Rep. Keith Ellison introduced the senator from Vermont, runners on the convention floor passed out signs emblazoned with Sanders’ familiar slogan: “Bernie — A Future to Believe In.” But Sanders’ royal-blue background and Jubilat font was gone, and Clinton’s light-blue background and Unity font had taken their place.

When Sanders finally strode onstage, the crowd cheered for two and a half minutes — an eternity in politics. Delegates were weeping. It felt like some sort of catharsis.

“Let me be as clear as I can be,” Sanders began. “This election is not about, and has never been about, Hillary Clinton or Donald Trump, or Bernie Sanders or any of the other candidates who sought the presidency. This election is not about political gossip. It’s not about polls. It’s not about campaign strategy. It’s not about fundraising. It’s not about all the things the media spends so much time discussing. This election is about — and must be about — the needs of the American people and the kind of future we create for our children and grandchildren.”

And while Sanders admitted that “no one is more disappointed than I am” by “the final results of the nominating process” — and while he refused to release his delegates, guaranteeing that Clinton will face a more robust vote of opposition during Tuesday’s roll call than any Democratic nominee since the 1980s — he spent the remainder of his speech testifying that Clinton was better than Trump on issue after issue: minimum wage, Citizens United, college affordability, climate change, health care, prescription-drug prices, immigration reform, criminal-justice reform, human rights.

“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,” Sanders concluded, urging his supporters not to “sit [this election] out.” “The choice is not even close.”

He added that Clinton would “make an outstanding president.” If anyone was still heckling, they were inaudible amid the cheers.

A disappointed supporter of former Democratic presidential candidate Sen. Bernie Sanders holds up her sign at the Democratic National Convention. (Photo: Mary Altaffer/AP Photo)

And that’s exactly what they did.

The response to the opening invocation by Reverend Dr. Cynthia Hale of Decatur, Ga., set the tone for the rest of the day. The start of Hale’s prayer didn’t mention politics. But then she uttered the name “Hillary Clinton.”

“We have an opportunity, O God,” Hale intoned, “to give undeniable evidence to our commitment to justice and equality by nominating Hillary Rodham Clinton as our candidate for the highest office in the land.”

A few catcalls echoed off the rafters. As Hale continued to speak, a rumble built in the arena. Soon, the booing overwhelmed her words. It was a stunning breach of convention etiquette.

The same thing happened again and again throughout the afternoon.

Former Massachusetts Rep. Barney Frank, a Clinton loyalist, was jeered when he stepped to the podium to deliver the Rules Committee report.

As Maryland Rep. Elijah Cummings lyrically extolled “the most progressive platform in party history,” Sanders fans opposed to Obama’s Trans-Pacific Partnership trade deal drowned him out.

Representative Elijah Cummings, D-Md., speaks at the Democratic National Convention. (Photo: Scott Audette/Reuters)

“No TPP!” they yelled for minutes on end.

Ohio Rep. Martha Fudge — Wasserman Schultz’s replacement as the permanent chair of the convention — had the temerity to admit that she was “excited to put Hillary Clinton and Tim Kaine in the White House.” Her confession — a fairly normal thing for a convention speaker to say about the party’s presumptive nominee — was greeted with a good 20 seconds of “Bernie! Bernie!”

“Excuse me! Excuse me!” Fudge shouted, as delegates from New Mexico, Michigan and Virginia kept booing and waving signs: “No,” “Nay,” “Feel the Bern.” Several Sanders supporters had crossed out Clinton’s “Love Trumps Hate” slogan and scrawled “Bernie Trumps Hillary” in its place.

“I intend to be fair, and I want to hear the varying opinions here,” Fudge continued. “I will be respectful of you. I want you to be respectful of me. We’re all Democrats, and we need to act like it.”

Fudge wasn’t the only Democrat who tried — and failed — to calm the crowd.

“Let’s show Donald Trump that we can work together,” said former Denver Mayor Wellington Webb. “Let’s cheer for Bernie tonight when he takes the stage. Let’s also cheer for Hillary, when she takes the stage on Thursday.”

Then Webb mentioned the prospect of a “Madam President.” Some Sanders folks resumed their booing; other pro-Bernie delegations protested in silence, pointedly refusing to applaud.

Sanders waded into the melee before arriving at the arena. When he told his delegates to support the Democratic ticket during a speech at the Philadelphia Convention Center, they booed him as well.

“We have got to elect Hillary Clinton and Tim Kaine,” Sanders said.

“We want Bernie!” the crowd chanted. “We want Bernie!”

“Brothers and sisters! Brothers and sisters!” Sanders interrupted. “This is the real world that we live in.”

As Yahoo News Senior National Affairs Liz Goodwin reported, the senator went on to plead with the leaders of his delegates — via text message — not to protest on the convention floor.

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

Later, Sanders emailed his delegates to say that the movement’s credibility would be “damaged” by “booing, turning of backs, walking out or other similar displays.”

The outbursts briefly subsided around dinnertime. Many Sanders delegates left their seats to find food; they had missed lunch to see the senator speak at the convention center. The program also shifted onto less provocative turf, at least for Democrats: unions, immigration, LGBT rights, Donald Trump.

Yet the dissenters eventually came roaring back. Appearing alongside Minnesota Sen. Al Franken, comedian Sarah Silverman, a longtime Sanders supporter, praised Bernie for “mak[ing] us understand what is possible.” But she also insisted that “a vital part of that movement is making absolutely sure that Hillary Clinton is our next president of the United States” — and the chanting started up again, with each side trying to overpower the other.

“Bernie! Bernie!”

“Hillary! Hillary!”

“Can I just say to the ‘Bernie-or-Bust’ people: You’re being ridiculous,” Silverman snapped, going off-script. “Sorry, I just had to add that.”