On Wednesday, 4Chan and Kiwi Farms, two of the most controversial social media sites on the internet, filed a federal lawsuit against the British government, arguing that the requirements of the UK’s Online Safety Act infringe on their Constitutional rights as American corporations.

In a filing submitted to the U.S. District Court in the District of Columbia, Preston Byrne and Ron Coleman, the team representing the two sites, said that their clients are being penalized by Ofcom, the agency that regulates online content in the United Kingdom, for “engaging in conduct which is perfectly lawful in the territories where their websites are based”.

4Chan and Kiwi Farms are widely considered to be two of the most toxic websites on the internet, and their userbases notoriously engage in the kind of online behavior the Online Safety Act seeks to penalize: racism, hate speech, harassment, spreading conspiracy theories, and bullying, among others actions. Kiwi Farms has turned into an organizational hub for aggressive harassment campaigns, particularly against women and trans people, that often bleed into the real world. 4Chan has also spawned massive harassment campaigns like Gamergate, as well as racially-motivated mass shootings, conspiracy theories like QAnon.

Both 4Chan and Kiwi Farms could face steep fines of up to £18 million if they fail to comply with Ofcom’s requirement that they regularly submit “risk assessment” reports about their userbase, due to their sites being accessible in the U.K. Earlier in August, Ofcom issued a provisional decision stating that there were “reasonable grounds” to believe 4chan was in violation of the requirement. In the filing, their lawyers argue that Ofcom is overreaching its legal authority by trying to apply British law to companies based in the U.S., where their behavior is protected by the U.S. Constitution and the American legal code, and seek to have a U.S. federal judge declare that Ofcom has no jurisdiction in this matter.

“American citizens do not surrender our constitutional rights just because Ofcom sends us an e-mail,” Byrne said in a statement to reporters.

The OSA’s requirements have drawn international backlash, as it’s not clear whether sites like Reddit, Bluesky and Wikipedia would be subjected to the same penalties. But the MAGA internet community — the core of the movement backing Donald Trump — has previously argued that the specifically targeted networks that hosted far-right content, and that the Biden administration allowed them to do so.

Byrne, who once represented the right-wing social network Parler, previously told The Verge that he’d believed that the Trump administration had tried working diplomatic backchannels in order to get Ofcom to back down. Though there’s no indication that the State Department has intervened, Byrne said that lawyers representing other websites facing similar issues with Ofcom were watching them closely: should 4Chan and Kiwi Farms, of all places, receive legal protection, it would stand to reason that they should, too. “I’m not going to go into details,” he said, “but suffice to say, there are plenty of lawyers interested in taking on Ofcom right now.”