Jeremy Rubin just wanted to speak out about the rise of white supremacist groups in the U.S. and raise some money to fight against those groups. But the Internet domain name he registered in late 2017 for his campaign—“fucknazis.us”—ran afoul of a U.S. Department of Commerce policy banning certain words from .US domain names. A government contractor took away his domain name, effectively shuttering his website. Last month, after EFF and the Cyberlaw Clinic at Harvard Law School intervened, Mr. Rubin got his site back.

A government agency shutting down an Internet domain based on the contents of its name runs afoul of the First Amendment. After a long back-and-forth with EFF and the Cyberlaw Clinic, the Commerce Department’s contractor Neustar agreed to give Mr. Rubin back his domain, and to stop banning “dirty words.” fucknazis.us has proudly returned to the Internet.

As anyone with a business or personal website knows, having a meaningful domain name can be the cornerstone of online presence. Mr. Rubin, moved to act after anti-Semitic and white supremacist incidents last summer, created a “virtual lapel pin” through the Ethereum computing platform as a fundraiser for opposition to these causes. The virtual pins, and the domain he registered to sell them, declared his message in a pithy fashion: “fucknazis.us”

The Internet’s domain name system as a whole is governed by ICANN, an independent nonprofit organization. While ICANN imposes questionable rules from time to time, a blanket ban on naughty words in domain names has never been one of them. Unluckily for Mr. Rubin, the .US top-level domain is a different animal, because it’s controlled by the U.S. government.

The .US domain was originally set up with a complex regional and topical hierarchy, but today anyone with a connection to the U.S. can register a second-level domain name under .US. Since 1998, it’s been controlled by the National Telecommunications and Information Administration (NTIA), a part of the Department of Commerce. And it’s managed by registry operator Neustar, Inc., under contract with NTIA.

Shortly after Mr. Rubin registered “fucknazis.us,” Neustar suspended the domain, calling it a violation of an NTIA “seven dirty words” policy, a phrase with particular First Amendment significance.

As a general rule, First Amendment law makes clear that the government can rarely impose restrictions on speech based on the content of that speech, and when it does, must show some level of necessity. The well-known case of Federal Communications Commission v. Pacifica Foundation upheld the FCC’s decision to reprimand, though not fine or revoke the license of, a public broadcaster after it aired George Carlin’s famous monologue “Filthy Words.” In so doing, the Court approved of the FCC’s definition of “indecency,” a word otherwise without a constitutional definition. But the Supreme Court explained that “indecency” as a legal concept was limited to over-the-air broadcast media, because broadcasts made use of limited radio spectrum, were a scarce and highly regulated public resource, and were easily overheard by children in their everyday surroundings. Many years later, the Supreme Court directly rejected the US government’s attempt to impose a similar indecency regime on the Internet, and that regime has never been applied to any medium other than over-the-air radio and television broadcasts.

Last month, we learned that Neustar and NTIA were reversing course, allowing Mr. Rubin to proceed with the use of fucknazis.us, and more generally removing these kinds of restrictions from future .US domain name registrations.

Thanks to the First Amendment, the .US domain, advertised as “America’s Address,” is a place where one can say “Fuck Nazis” without censorship.

Corrected to reflect that .US originally allowed non-government registrants, but only at third- and fourth-level domains.