The U.S. Supreme Court decision to strike down a Montana ban on corporate money in politics drew a stinging criticism from U.S. Rep. Keith Ellison, D-Minn., a constant critic of the influence that wealthy donors have on elections.

In a 5 to 4 decision, the court ruled against a century-old law that barred direct corporate contributions to political parties and candidates.

"This ruling compounds the damage to our democracy already done by the Citizens United v FEC decision, which has allowed millions of untraceable dollars to overwhelm our federal, state and local elections," Ellison said in a joint statement with his Congressional Progressive Caucus co-chair, U.S. Rep. Raul Grijalva of Arizona.

In the Montana case, the justices voted along the same lines as the Citizens United v. FEC case when they ruled that corporate money is speech, a decision that paved the way for corporations to spend unlimited amounts of money on elections.

"The precedent set by that decision and reaffirmed today allows outside groups to trump popular state and federal laws that keep elections in the hands of the people. Montana's campaign finance law kept campaigning costs low for candidates and ensured that voters had the most powerful voice in politics," the statement from Ellison and Grijalva read." ... we know what happens next. Wealthy donors, corporations and special interests will now have unchecked influence over Montana's political process."