The Democratic National Convention kicked off in Philadelphia today under a cloud of controversy, one that is energizing Bernie Sanders supporters who say they are vindicated by it.

On the eve of a convention that is meant to solidify party unity in the wake of a divisive primary season between Sanders and Hillary Clinton, the party was instead dealing with the fallout from allegations that it was biased and tried to undermine his campaign and that leaked emails now prove it. 

As delegates arrived from around the country Sunday and Sanders supporters were demonstrating in the streets during an already planned rally, the DNC's chairwoman announced she would step down at the end of the week when the convention is over. The move is seen as a swift attempt to deal with the controversy and smooth over the tension this has caused among delegates.

Debbie Wasserman Schultz's resignation is what Sanders wanted all along; he complained about her conduct long ago, and in a statement Sunday he called it the "right decision."

Sanders followed up that sentiment when he met with his delegates Monday afternoon. "Her resignation opens up the possibility of new leadership at the top of the Democratic Party that will stand with working people and that will open the doors of the party to those people that want real change," he told them.

His delegates wholeheartedly agree and are happy to see Schultz go.

"The most exciting part of the convention already happened, Debbie Wasserman Schultz stepped down so that's awesome," said Natalie Vowell, ahead of Sanders's appearance. "I think we might have a more fair convention now. It may be too late, but that's pretty exciting to me."

Another delegate wanted more action to be taken beyond the resignation. "That's not enough. That's a step acknowledging a problem but that does nothing to rectify the problem," said Amy Buchanan, a delegate from Nebraska who was rushing through the halls of Philadelphia's convention centre Monday morning.

Abby Davis, who was walking alongside her and similarly wearing a Sanders T-shirt, said the leaked emails do little to help engender goodwill among Sanders supporters, who were already angry and bitter with the DNC.

"We keep hearing about party unity and they aren't considering the fact that they've actively worked against our candidate. That doesn't make us want to unify with them," the 18-year-old said.

Emotions are high

The emails published on Friday by Wikileaks reveal embarrassing messages by Schultz, a Florida Congresswoman, and other DNC staff. The DNC is supposed to remain neutral and not favour one candidate over another, but the emails showed some staff clearly had their preferences. They criticized the Sanders campaign and some discussed how to undercut it.

It's not known who hacked into the DNC's email system or who leaked nearly 20,000 emails, but fingers are pointing at Russians. Clinton's campaign has suggested it might be an effort to help Republican nominee Donald Trump get elected.

Sanders supporters say the emails prove what Sanders argued throughout the primaries — that the DNC wanted Clinton to win and rigged the process to ensure that happened. The Vermont senator had pointed to a number of examples including a debate schedule that Sanders felt would give him less exposure, a fundraising arrangement between the party and Clinton, and Clinton supporters getting key roles on convention committees.

"We did think that they were rigging the primaries and it turned out to be true. We are not surprised but the emotions are really high," said Daniel Carter, a delegate from Florida. "There are some pissed off people."

Daniel-Carter

Daniel Carter, 19, is a Bernie Sanders delegate from Florida who said the leaked emails from the Democratic National Committee prove the party was trying to undermine the Sanders campaign and his supporters are angry about it. (Meagan Fitzpatrick/CBC News)

Carter stopped to talk as he was leaving a rally for Sanders on Sunday night in the park across from the Wells Fargo Center, where the convention's evening speeches take place and where Sanders is due to address the party Monday night.

The 19-year-old college student said he arrived in Philadelphia that day excited and ready to celebrate everything Sanders had accomplished, but this controversy is changing the dynamic.

'It was validating'

"What they did to us is ridiculous. They laughed at us ... like we were nothing," Carter said, calling the emails "the last straw" for a lot of Sanders supporters. "A lot of people are angry and fed up."

Erin Kreider was also at the Sanders support rally and said the leaked emails exposed to the public what they've known all along: "This has been rigged."

Erin-Kreider

Andrew MacNamee, left, and Erin Kreider, are Bernie Sanders supporters from Lancaster, Pennsylvania and attended a Sanders support rally on Sunday, July 24 in Philadelphia. (Meagan Fitzpatrick/CBC News)

Kreider, 30, said Sanders supporters had been viewed as conspiracy theorists but now that's going to change. "We don't have to be that fringe element anymore, because we're right. We've known this was going on all along. It was validating."

The email scandal is fuelling resentment that Sanders voters already had toward the DNC and it's threatening to hinder Clinton's campaign slogan and a theme of the convention, "Stronger Together."

Sanders, however, is expected to still play his part in forging party unity at the convention.

When he spoke to his delegates Monday afternoon, he urged them to continue to fight for issues like immigration and criminal justice reform and also urged the party to unite to defeat Donald Trump, whom he called a "bully" and "danger" to the country.

"We have got to elect Hillary Clinton and Tim Kaine," said Sanders, referring to Clinton's vice-presidential pick. The comment drew a mix of cheers and boos from the crowd.

Clinton jeered at Sanders rally1:45

Sanders acknowledged defeat and endorsed Clinton earlier in the month, though he has not suspended his campaign and released his delegates. They will still cast their votes for him when there is a roll call vote by state on Tuesday.

Clinton campaign officials tried to downplay the effect of the story on party unity at a news conference Monday morning. "Our party is coming together here to unify, to elect Hillary Clinton and defeat Donald Trump and that's what you are going to see today," said Robby Mook, campaign manager for Hillary for America.

Mook said he's excited for Sanders to speak Monday night and he anticipates Clinton's former rival will "double-down" on his endorsement of her.

Sanders supporters say also getting in the way of repairing the damage caused by the emails is Clinton's reaction to it. They aren't pleased that she gave Schultz a role in her campaign.

Schultz given new campaign role

Clinton said in a statement Sunday that Schultz will serve as honorary chair of her 50-state program to help elect Democrats across the country and she will serve as a campaign surrogate and campaign for her.

Tao Weilundemo, a Missouri delegate, said the resignation at first appeared as a conciliatory move but then Clinton's praise for Schultz "felt like cronyism."

"Any goodwill that might have been earned by her resigning evaporated with that in my opinion," he said outside the room where he would be hearing from Sanders. "It feels like she got rewarded for whatever she did to help Hillary get to the position she's at."