Bernie Sanders has urged supporters to line up behind Democrat Hillary Clinton while claiming victory in deposing and sidelining a top party official.
Some of his supporters jeered in disapproval, indicating that turmoil at this week’s Democratic National Convention in Philadelphia will not end with the departure of the party chairman, Representative Debbie Wasserman Schultz of Florida.
Speaking to his convention delegates, just hours before the Democrats opened a convention to nominate his primary rival, the Vermont senator tried to settle growing tensions between his supporters and the party rank-and-file lining up behind Mrs Clinton.
A fresh email controversy, appearing to show bias by party officials against Mr Sanders, has made that task harder just as the national spotlight turns to the Democrats’ rally behind Mrs Clinton.
“Brothers and sisters, this is the real world that we live in,” Mr Sanders told his audience, raising his hand in an effort to quiet them.
Republican presidential nominee Donald Trump is “a bully and demagogue”, he said, who must not win the White House.
The remarks were met with boos and grumbling from supporters clearly not ready to give up the fight for what he calls his “political revolution”.
Mr Sanders tried to persuade them they had already won by helping to create what he called the “most progressive Democratic platform in the history of the party”.
And he, too, celebrated the removal of Ms Wasserman Schultz after the email hack.
“Her resignation opens up the possibility of new leaders at the top of the Democratic Party that will stand with working people,” he said.
As Mr Sanders spoke, Ms Wasserman Schultz announced she would not gavel in the convention, recognition that her presence onstage would only showcase Democrats’ deep divisions. The Florida congresswoman was greeted with boos on Monday morning by delegates who would certainly have repeated the spectacle.
For Democrats who spent last week voicing criticism over the Republicans’ troubled convention in Cleveland, the scene was a painful reminder of their own problems.
On the eve of the four-day spectacle, the 19,000 hacked emails published by WikiLeaks appeared to show top officials at the supposedly neutral Democratic National Committee working to tip the scales towards Mrs Clinton. Ms Wasserman Schultz denied the accusation but was forced out as chief on Sunday.
The FBI issued a statement on Monday saying it is investigating the hack.
“A compromise of this nature is something we take very seriously, and the FBI will continue to investigate and hold accountable those who pose a threat in cyberspace,” it said.
Clinton campaign officials pointed the finger at Russian military intelligence agencies. They accused Russia of trying to meddle in the US election and favouring Republican nominee Mr Trump.
“We don’t have information right now about that, but what we have is a kind of bromance going on between Vladimir Putin and Trump which is distinct from this leak,” Clinton adviser John Podesta said in an MSNBC interview.
Mr Trump dismissed the suggestion in a tweet: “The joke in town is that Russia leaked the disastrous DNC emails, which should never have been written (stupid), because Putin likes me.”
It was not immediately clear how WikiLeaks received copies of the internal Democratic emails. Party officials learned in late April that their systems had been attacked after they discovered malicious software on their computers.
A cybersecurity firm they employed found traces of at least two sophisticated hacking groups on their network – both of which have ties to the Russian government. Those hackers took at least a year’s worth of detailed chats, emails and research on Mr Trump, according to a source.
The emails re-emphasised a rift that threatens to undermine the Democrats’ attempt to display four days of focus on putting Mrs Clinton in the White House.
The party announced on Monday it would kick off its convention with a lineup of speakers aimed at easing the tensions. Massachusetts Senator Elizabeth Warren, a progressive favourite, will deliver the convention keynote. Mr Sanders and first lady Michelle Obama will also take the stage.
Republicans relished the Democrats’ pre-convention tumult, just days after they bumped and bumbled through their own gathering. Mr Trump declared on Twitter: “The Dems Convention is cracking up.”
Resistance to Mrs Clinton was on display during a demonstration at City Hall, where hundreds of Sanders supporters chanted “Nominate Sanders, or lose in November!”
But others were falling in line behind Mrs Clinton.
Ohio’s Michael Skindell, a Sanders delegate, said he planned to “strongly support the nominee of the party”.
Mrs Clinton campaigned in Charlotte, North Carolina, on Monday, serving up a harsh critique of Mr Trump’s foreign policy and what she said was his “trash talk about America”.
Speaking to a convention of the Veterans of Foreign Wars, Mrs Clinton slammed many of his positions, vowing to stand by American allies, fight dictators and listen to the advice of military officials.
“You will never hear me say I only listen to myself on national security,” she said.
Ahead of her speech, she secured the endorsement of retired general John Allen, former deputy commander of US Central Command and a former commander of the International Security Assistance Force, overseeing Nato troops in Afghanistan.
Mrs Clinton is within days of her long-held ambition to become the party’s official presidential nominee. She will formally accept the nomination on Thursday.
President Barack Obama will speak on Wednesday night, while other high-profile speakers include former president Bill Clinton and vice president Joe Biden.