The demonstration was part of a series of "Democracy Spring" protests planned in Washington this week by a coalition of groups.
The demonstrators chanted slogans like "one person, one vote" and "money out of politics" as they sat on the East Front of the Capitol. One sign read "Things go better without Koch," a reference to the conservative billionaire businessmen David and Charles Koch, who have promised to lead an almost $900 million campaign to back favored candidates this election cycle.
The demonstrators also protested state voter identity laws, saying they suppress voter participation, particularly among Democratic-leaning minorities and young people. Another chant protested Democratic "superdelegates" — party figures, such as members of Congress, who can vote for any candidate at the Democratic National Convention but are not elected by primary elections or at party caucuses.
Police led dozens of protesters away in plastic handcuffs into a bus and shuttle vans, prompting cheers from the two groups of protesters, which were separated by a large number of police.
U.S. Capitol Police said Monday evening that more than 400 people had been arrested for unlawful demonstration activity.
Many of the protesters had marched from Philadelphia to Washington over the past week.
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