The Supreme Court building in Washington. (J. Scott Applewhite/Associated Press)

THE UNITED STATES is engaged just now in a freewheeling debate about — freewheeling debate. Or, to put it more precisely, about how freewheeling debate should normally be. The struggle is being waged across various battlegrounds — college campuses, social media, New York theater, even the air-conditioned offices in which federal employees decide whether to protect trademarks, such as that of Washington’s National Football League franchise.

Now comes the Supreme Court with a strong statement in favor of free speech, to include speech that many find offensive. With the support of all eight justices who participated in the case (new Justice Neil M. Gorsuch being the exception), the court struck down a 71-year-old law requiring the Patent and Trademark Office to deny registration to brands that may “disparage” people or bring them “into contemp[t] or disrepute.” The ruling means that a dance-rock band may henceforth call itself “the Slants” on the same legal basis that, say, Mick Jagger’s bunch uses “the Rolling Stones” — even though many Asian Americans find the term derogatory and demeaning.

The justices were obviously, and properly, influenced by the fact that the Asian American members of the Slants took the name in a bid to “reclaim” that slur as something more positive and prideful. To apply the existing disparagement proviso in the statute despite the band’s expressive intent would not merely have exercised government control over government expression, implicit in trademark registration, as the Obama administration argued when the court heard the case shortly before Inauguration Day this year. It would, as the justices ruled, have put the government in the business of picking and choosing among points of view, a role that the court has repeatedly forbidden it to perform.

To be sure, the opinion for the court by Justice Samuel A. Alito Jr., a staunch conservative, came accompanied by a concurring opinion in which Justice Anthony M. Kennedy and three liberal colleagues, Ruth Bader Ginsburg, Elena Kagan and Sonia Sotomayor, set out doctrinal nuances. But what was striking about all the opinions Monday was the strength with which every member of the court embraced the First Amendment, strongly enough to protect even speech that many people legitimately find hateful or offensive. “The proudest boast of our free speech jurisprudence is that we protect the freedom to express ‘the thought that we hate,’ ” Mr. Alito wrote. The concurring opinion followed with the rationale underlying that jurisprudence: “A law that can be directed against speech found offensive to some portion of the public can be turned against minority and dissenting views to the detriment of all.”

This is strong medicine, both in terms of the support it offers free speech and in terms of what it requires of those who do take offense at expressions likely to enjoy court protection as a result of this opinion — specifically the Washington football team’s name, which was also the subject of a suit against its trademark. The answer, in our view, is to redouble all lawful efforts to get that name changed, even if a federal lawsuit probably can’t be one of them. As the court’s decision reminds us, constitutional and decent are not the same thing.