Story highlights Protestors are training ahead of the Democratic National Convention

They plan to be in the streets in Philadelphia next month

(CNN) The progressive political movement emboldened by Bernie Sanders' insurgent campaign is preparing to "crash" next month's Democratic National Convention, demanding the party establishment take steps to reject corporate influence and reform its nominating process.

"If the Democratic Party wants to put on a $50 million infomercial saying, 'Hey vote for us,' without committing to make this the last corrupt, billionaire-nominated voter suppression-marred election, then we're going to crash the party," said Kai Newkirk, director of Democracy Spring, a nonpartisan activist coalition dedicated to "mass nonviolent action" against big money in politics.

The mostly independent organizers behind Sanders' "political revolution" emerged from the "People's Summit" in Chicago this weekend primed to launch a new wave of pressure on the party elite. Former Ohio state Sen. Nina Turner, a top surrogate for the Vermont senator's campaign, gave a stem-winding call to action after telling reporters she expected "hundreds of thousands of people out there" in Philadelphia at the convention.

"That's America -- we are about the protest," she said. "We are about having a righteous indignation. We can no longer stand by and have business as usual."

In April, Democracy Spring and its allies launched an eight-day "direct action" on the steps of the U.S. Capitol. More than 1,400 people were arrested, but not before nearly 100 members of Congress called for hearings on the campaign finance reform and voting rights measures lobbied for by protesters.

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