ASHBURN, Va. — Washington’s NFL team on Thursday formally appealed a ruling that stripped the team of trademark protection, the latest legal maneuver in the franchise’s attempt to defend its name “Redskins” against those who consider it a racial slur.

The team announced that it had filed its complaint in the U.S. District Court for the Eastern District of Virginia and that it “points out the many errors” in the decision by the U.S. Patent and Trademark Office.

The office’s Trademark Trial and Appeal Board voted 2-1 on June 18 to cancel six uses of “Redskins” trademarked from 1967 to 1990, saying the name is “disparaging of Native Americans.”

“We believe that the Trademark Trial and Appeal Board ignored both federal case law and the weight of the evidence, and we look forward to having a federal court review this obviously flawed decision,” Redskins lawyer Bob Raskopf said in the team’s statement.

The team had previously said it would appeal the ruling and had two months to do so. The trademark protection remains while the matter makes its way through the courts, a process that could take years. A ruling by the trademark board in 1999 was overturned on a technicality in 2003. Native Americans have been challenging the trademark since 1992.

The teams says it will ask the court to consider “serious constitutional issues,” including whether the ruling penalizes the team’s right of free speech and whether the team has been unfairly deprived of “valuable and long-held intellectual property rights.”

The group of five Native Americans that is challenging the name is equally confident.

“This effort is doomed to fail,” said Amanda Blackhorse, the lead plaintiff. “But if they want to prolong this litigation which has already gone on for 22 years, I guess they have that prerogative.”

The team has been under sustained pressure to defend the name over the last 18 months, with major political, church and sports figures joining the debate and saying it should be changed.

Team owner Dan Snyder has vowed never to change the name, calling it a “badge of honor.”

“If people wouldn’t dare call a Native American a ‘redskin’ because they know it is offensive, how can an NFL football team have this name?” Blackhorse said. “We know that time is on our side for a change in the team’s name, and we are confident we will win once again at this stage of the litigation.”