The U.S. Capitol Police on Wednesday arrested 85 demonstrators outside the Capitol Building, days after arresting 400 people in a similar protest.
The demonstrations on Monday and Wednesday were part of a campaign called "Democracy Spring," which aims to call attention to what says is a corrupt campaign finance system.
Some of the protesters marched the 150 miles to Washington from Philadelphia, organizers said.
The campaign's demands include that Congress pass legislation that would strengthen voting rights and reduce the influence of money in politics.
The protesters also want Congress to confirm a nominee to the Supreme Court who would "vote to uphold political equality."
In a statement, the U.S. Capitol Police said most of those arrested on Monday and Wednesday would be charged with "crowding, obstructing, or incommoding."