The United States on Thursday asked the European Union’s General Court to let it intervene on the side of Elon Musk and his social media platform X, which are seeking to overturn a fine for breaching the bloc’s online content rules.

Musk and X, formerly known as Twitter, are challenging a 120-million-euro ($136 million) penalty imposed by Brussels under its landmark digital rules.

The US Justice Department said it had filed an application at the EU’s second-highest court backing Musk and X’s bid to annul the European Commission’s December 2025 decision, the first fine ever issued under the Digital Services Act (DSA).

The DSA, which fully took effect in 2024, requires online platforms to do more to tackle illegal and harmful content and to be more transparent about how their systems work.

Violations can bring fines of up to six percent of a company’s global annual turnover.

The law has become a flashpoint between Washington and Brussels. President Donald Trump’s administration and the US tech industry have cast it as a tool of censorship, a charge the EU rejects.

“The European Commission inappropriately attempted to expand its regulatory authority to reach American companies not present or operating within its jurisdiction,” said Assistant Attorney General Brett Shumate.

“We will not tolerate the European Commission engaging in regulatory overreach to try and control American engines of innovation and economic growth,” he added.

The commission fined X for breaching transparency obligations, using deceptive design in its paid blue checkmark system and denying researchers access to public data.

Trump called the fine censorship, and a few weeks later the US State Department announced sanctions on five people, including former EU commissioner Thierry Breton.

X, whose EU headquarters are in Ireland, filed its appeal in February, arguing that the fine violated its due process rights. But the company has also moved to comply with the decision.

In July, the commission accepted X’s plan to remedy the violations, which includes widening researchers’ access to data, such as advertising information, with the changes subject to an independent audit.

X had already relabeled its blue checkmarks “premium” instead of “verified.”