Delivering a blow to Washington, DC’s NFL franchise, the US Patent and Trademark Office on Wednesday canceled six federal trademark registrations for the Washington Redskins, on the grounds that the name is “disparaging to Native Americans.”

The cancellation is based on the grounds that racist, offensive or disparaging names are illegal under federal trademark laws.

In its opinion, first reported by Think Progress, the office ruled that, “based on the evidence properly before us,… these registrations must be cancelled because they were disparaging to Native Americans at the respective times they were registered.”

The ruling resulted from a complaint filed by a group of Native Americans before the Patent Office’s Trademark Trial and Appeal Board. And it’s the latest move in a burgeoning national campaign aimed at forcing team owner Daniel Snyder to change the name, despite his iron-clad commitment to it.

The controversy has led to a television ad broadcast during this year’s NBA Finals, national news coverage and protests at the team’s home stadium. Here’s the ad:

It even reached the floor of the U.S. Senate: Majority Leader Harry Reid, a Nevada Democrat, argued that the name is racist, sparking a fierce Twitter war over his remarks.

On Tuesday, Reid reiterated his position: he vowed not to attend another Washington NFL Franchise game – a coveted perk among members of Congress – until Snyder changes the team name.

“It is untoward of Daniel Snyder to hide behind tradition,” Reid said in an April floor speech, noting the NBA forced L.A. Clippers owner Donald Sterling to sell his team after racist remarks he apparently made were caught on tape.

“That’s what [Snyder] says in refusing to change the name of the team … what tradition?” Reid said.  “A tradition of racism is all that name leaves in its wake.