In a ruling that could bolster the Washington Redskins’ legal case to keep the registered trademarks to their name, a federal appeals court struck down part of a law Tuesday that let the government reject trademarks it deemed offensive or disparaging to others.

The United States Court of Appeals for the Federal Circuit in Washington made the ruling in a case involving an Asian-American dance-rock band that sought to register a trademark for its provocative name, the Slants. The court said the First Amendment “forbids government regulators to deny registration because they find the speech likely to offend others.”

Writing for the majority, Kimberly A. Moore, a judge on the appeals court, said: “It is a bedrock principle underlying the First Amendment that the government may not penalize private speech merely because it disapproves of the message it conveys.”

The ruling overturned a previous decision by a three-judge panel of the court that had upheld the United States Patent and Trademark Office’s rejection of the band’s application.