President Trump’s use of painful tariffs against Brazil has so far not sprung his political ally Jair Bolsonaro from house arrest as he awaits trial on charges of plotting a coup.

But the levies appear to be having more success in opening doors for America’s Big Tech companies as they seek to influence the rules governing them.

The companies, which have been aggressively courting Mr. Trump, suddenly have new leverage in Brazil’s halls of power. Against a backdrop of a 50 percent tax on key Brazilian products, the firms are being welcomed to meetings with Brazilian officials and justices of the Supreme Court, as new regulation is being shaped on everything from online speech to artificial intelligence, according to several people with knowledge of the matter.

“Everything seems to be part of ‘the deal,’” said Anupam Chander, a law and technology professor at Georgetown University. “What might have been seen as Brazilian domestic policy suddenly becomes part of a trade agenda.”

Mr. Trump has had less success using a 50 percent tax on key Brazilian products as a bully pulpit to force the judicial branch to drop the case against Mr. Bolsonaro. The former Brazilian president falsely claimed that the last election was rigged to favor his rival, Luiz Inácio Lula da Silva.

Brazil has insisted that nobody can meddle in its judicial affairs, and the Supreme Court justice overseeing Mr. Bolsonaro’s case, Alexandre de Moraes, has not been swayed, even when the United States imposed on him some of the most drastic sanctions in its arsenal.