BRASILIA, Aug 19, 2025 (BSS/AFP) - Brazil's Supreme Court ruled on Monday that foreign legislation did not have jurisdiction in its country, after the United States used a law to sanction a judge on the court.

Washington used the Magnitsky Act, a US law which provides for sanctions against individuals accused of human rights violations around the globe, to impose restrictions on Supreme Court Justice Alexandre de Moraes, who is presiding over the trial of former president Jair Bolsonaro's alleged coup plot.

Moraes is also the judge which banned the social network X, formerly Twitter, in Brazil last year.

"Judge Flavio Dino, of the Federal Supreme Court, suspended the effectiveness of judicial decisions, laws, decrees, and executive orders of foreign nations in our country," Brazil's high court said in a statement.

According to the Constitution of Brazil, foreign court decisions "can only be enforced in Brazil upon approval or in compliance with international judicial cooperation mechanisms," the court said.

Dino said this same principle applied to recent decisions from UK court rulings made against the Brazilian Mining Association (Ibram) for the Mariana and Brumadinho dam disasters.

Although the ruling did not explicitly mention the Magnitsky Act, a Brazilian court source told AFP that the ruling "in theory" invalidates the law in Brazil -- though Washington has already contested this interpretation.

"No foreign court can invalidate United States sanctions -- or spare anyone from the steep consequences of violating them," the US government's Bureau of Western Hemisphere Affairs said in a statement on X after the ruling.

"Alexandre de Moraes is toxic to all legitimate businesses and individuals seeking access to the US and its markets," it continued.

"US persons are prohibited from transacting with him and non-US persons must tread carefully: those providing material support to human rights abusers face sanctions risk themselves."

The United States at the end of July had blocked all of Moraes' assets in the country as a result of his work on the Bolsonaro trial.

The case against the former Brazilian president, an ally of US President Donald Trump, has sparked a diplomatic and trade spat between Brasilia and Washington.

The verdict for the trial is expected to be announced by the court between September 2 and 12.