Bill Clinton takes center stage Tuesday at the Democratic National Convention, tasked with reassuring the faithful that his wife Hillary is the candidate best suited to stop Donald Trump in November.
After a contentious opening day in which many raucous and devoted Bernie Sanders supporters refused to acknowledge the inevitability of Clinton becoming their flagbearer, the former president in chief will seek to heal the party's divisions and bring about the unity it craves.
Before her husband delivers the keynote address for Day 2, the convention's 4,764 delegates will hold their roll call vote to formally anoint Clinton as their nominee -- a historic moment that will make her the first woman to serve as flagbearer of a major US party.
A dose of political theater could be in store, however, as Clinton's chief Democratic primary rival Sanders was seeking to place his name in nomination during Tuesday's vote.
If successful, such a move could serve as a powerful reminder of the impact that Sanders has had on the campaign and would likely fuel Sanders delegates' argument that there is one final, last-gasp effort to derail the Clinton express.
The convention's opening day reflected a startling amount of discord within the party, which had sought to show far more unity than their Republican counterparts. Boos and jeers from disgruntled Sanders supporters tainted the session.
Michelle Obama appeared to soothe some of the Sanders zealots, as she delivered a heartfelt endorsement from one first lady to another and hailing the inspirational power of possibly having a first female US president.
"In this election, I'm with her," Obama said.
She offered a thinly veiled jab at Trump while discussing how her family has had to adapt to the shrill tone of today's politics.
"We insist that the hateful language they hear from public figures on TV does not represent the true spirit of this country," the first lady said in a message that Democrats will hope resonates with fathers and mothers voting in November.
"Our motto is, 'when they go low, we go high.'"
The passionate delivery prompted her husband Barack Obama, who addresses the convention on Wednesday, to tweet his appreciation of her "incredible speech."
"Couldn't be more proud & our country has been blessed to have her as FLOTUS," he posted on Twitter.
"I love you, Michelle."
Sanders had called on his flock to get behind Clinton twice on Monday before his primetime endorsement speech.
That included a text message to supporters asking them not to protest on the floor of the convention, as a "personal courtesy" to him.
But Sanders' self-styled "political revolution" appeared to have transformed into a revolt.
Sanders himself was booed by some sections of the audience when he told the crowd: "Hillary Clinton will make an outstanding president and I am proud to stand with her tonight."
Michigan delegate Charles Niswander, 28, said he and other Sanders delegates would never line up behind Clinton.
"None of them want her. The people who voted for Bernie," Niswander said.
The party is reeling from leaked Democratic National Committee emails which show nominally neutral party staff trying to undermine Sanders' campaign and questioning his Jewish faith.
WikiLeaks at the weekend released nearly 20,000 emails from between January 2015 and May 2016, gleaned by hackers who apparently raided the accounts of seven DNC leaders.
The Federal Bureau of Investigation said it was investigating the "cyber intrusion," which the Clinton campaign blamed on Russian hackers it said are bent on helping Trump.
Sanders lost to Clinton in the primary handily. But the scandal has angered his already embittered supporters, who believe the deck was stacked against them.
The boos and jeers inside the convention suggested there was much healing still to be done.
"There is obviously more than four days' work necessary to heal all the wounds, and everybody accepts that," said Clinton delegate Josep Carlson, 64, of Massachusetts.
Bill Clinton's highly anticipated address could jump-start that process.
The 69-year-old Democratic icon, while no longer the charismatic speaker he once was, remains a powerful force on the national stage.
He has played such a role before. At the 2012 Democratic convention, he delivered closing arguments for why Barack Obama should be re-elected, a voice of experience explaining Obama's policies in clear, cogent detail and why he felt Republican policies were failing.