The EU’s top court on Tuesday once again slapped down Hungary over a rule-of-law issue, ruling that the country’s supreme court had improperly interfered with and disciplined a lower court judge.

The decision touched on a topic of friction between Brussels and Budapest: whether Hungarian judges can freely submit questions to the Court of Justice of the EU.

Tuesday’s ruling arose from a case involving a Swedish citizen facing criminal procedures in Hungary and whether that individual was provided proper translation services.

The judge overseeing the case asked the EU court to determine whether Hungarian law on the matter was compatible with EU law. But after doing so, the Hungarian supreme court stepped in and preemptively ruled the question was not relevant to resolving the dispute, declaring the request unlawful. Disciplinary procedures were then launched against the judge.

Following the supreme court’s ruling, the lower court judge again turned to the EU court, asking it to weigh in.

In Tuesday’s ruling, the European Court of Justice dismissed the Hungarian supreme court’s logic. And, it added, the lower court judge can’t be punished for taking such a step.

“Such proceedings are liable to deter all national courts from making references for a preliminary ruling, which could jeopardise the uniform application of EU law,” the ruling reads.

The decision is just the latest in a long-running spat between Brussels and Budapest over the rule of law. The two sides have clashed for years on numerous issues — primarily judicial independence, LGBTQ+ and refugee rights, corruption and media freedom. In response, Hungarian Prime Minister Viktor Orbán has repeatedly accused Brussels of working against the country’s national interest and meddling in its internal politics.

The standoff has escalated in recent weeks.

Just last week, the EU’s highest court ruled that a controversial Hungarian legislation criminalizing certain assistance for asylum seekers violated EU law.

The European Commission is also withholding the approval of billions in pandemic recovery funds from Hungary over corruption concerns.

More broadly, the Commission sent Hungary a letter over the weekend requesting more information about how EU money was disbursed in Hungary, as well as how judicial independence was being upheld. The move marked an informal first step toward triggering a never-before-used mechanism that could cut off some EU money to Hungary.