Elon Musk has found a powerful ally in his battle with Brussels. The US government wants to join his court fight against the first fine under the EU’s digital rulebook. The outcome could decide how far Europe can reach into American tech.

Governments rarely back a billionaire in a foreign court. The United States now wants to do just that. On 24 September, the US Department of Justice asked the General Court, the EU’s second-highest court, to let it join two cases. Both target a European Commission decision from 5 December 2025. X Internet and X Holdings filed one case. Elon Musk filed the other in his own name.

That decision fined X €120m. It was the first penalty ever under the Digital Services Act (DSA). The Commission found three problems. Anyone could buy a ‘verified’ blue checkmark without real identity checks. The advertising repository was hard to search, and X shut researchers out of its public data. “Deceiving users with blue checkmarks, obscuring information on ads and shutting out researchers have no place online in the EU,” Commission Executive Vice-President Henna Virkkunen said in December 2025, when the fine was first announced.

Musk himself on the hook

Washington’s objection goes further than checkmarks. According to the Justice Department, X and Mr Musk share liability for the fine. The Commission based the sum on the global turnover of the ‘single economic unit’ that Mr Musk controls, or that of X Holdings. The US says this goes too far. In its view, the decision reaches Mr Musk personally and firms with no link to X.

“The European Commission inappropriately attempted to expand its regulatory authority to reach American companies not present or operating within its jurisdiction,” said Brett Shumate, head of the department’s Civil Division. EU court rules let any country join a case if it has a stake in the outcome. The State Department helped to draft the filing. That shows how seriously the administration takes the dispute.

The judges must now decide whether to let the US in. According to the Justice Department, this is the first challenge to a DSA fine to reach the court. X filed its appeal on 16 February. It accuses the Commission of a sloppy investigation and grave procedural errors. It also claims it did not get a fair defence and hints at bias.

Behind the legal fireworks, X has quietly started to comply. In July, the Commission accepted its action plan. X promised a more searchable ad repository with API access. Eligible researchers will get faster data access free of charge. X has six months to deliver, and an independent auditor will then check the results. Separately, X has renamed its blue checkmarks ‘premium’ instead of ‘verified’.

Transatlantic row with a long tail

The fine has strained EU–US relations from day one. US Secretary of State Marco Rubio called it an attack “on all American tech platforms and the American people by foreign governments”. The Office of the US Trade Representative threatened fees or restrictions on European service firms. It named Accenture, DHL, Siemens, and Spotify. Weeks later, the State Department sanctioned five people, including former EU commissioner Thierry Breton.

We will not tolerate the European Commission engaging in regulatory overreach to try and control American engines of innovation and economic growth.
— Brett Shumate, US Assistant Attorney General

Mr Shumate raised the stakes this week. “We will not tolerate the European Commission engaging in regulatory overreach to try and control American engines of innovation and economic growth,” he said. Brussels shrugs it off. Asked what the move means for EU–US relations, Commission spokesperson Thomas Regnier said on 25 September: “From our side, absolutely nothing.” The Commission has “a very solid case” and is “absolutely ready to defend its position in court”, he added. Did Washington warn Brussels in advance? “We do not need to be informed about anything,” Mr Regnier said. In his view, the EU–US tariff deal is not at risk either.

The case matters beyond X. The platform still faces an open DSA probe into illegal content and information manipulation. That probe began in December 2023. A newer one looks at sexually explicit deepfakes made with its Grok chatbot. In May, the Commission fined Chinese marketplace Temu €200m for failing to assess the risk of illegal goods. A ruling is likely years away. Whatever the judges decide, they will set the first legal benchmark for DSA enforcement.