Brazil's Supreme Court was caught off-guard by Justice Alexandre de Moraes' decision late on Monday to place former President Jair Bolsonaro under house arrest, two sources at the court told Reuters on Tuesday.

The order underscores Moraes' readiness to act on his own despite both polarisation among Brazilians on the issue and rising tensions with the White House.

It came just days ahead of the introduction of 50% tariffs on Brazilian goods entering the United States.

U.S. President Donald Trump imposed the levies as a reaction to what he has characterized as a "witch hunt" led by Moraes against Bolsonaro, who is standing trial under charges of plotting a coup to overturn his 2022 electoral defeat. Bolsonaro has denied wrongdoing and described Moraes as a "dictator."

Moraes' ruling has sparked concern within the Brazilian government that Trump could retaliate by inflicting further damage to Brazil's economy, two sources close to President Luiz Inacio Lula da Silva's inner circle told Reuters.

But Brazilian officials are not planning to push back against Moraes. The two court sources, one of whom is a justice, told Reuters that the other Supreme Court justices were supportive of Moraes, while those close to Lula said the president has neither the willingness nor the ability to influence the Supreme Court.

"It doesn't change our approach in the slightest," said the justice, who asked not to be named to discuss the matter candidly.

The Lula administration is instead planning policies to support those industries likely to be hardest hit by Trump's tariffs and to keep diplomatic channels open with Washington, said the political sources.

But the Moraes move could create obstacles for the Brazilian negotiators, said Fabio Medina Osorio, Brazil's former attorney general.

"This decision can certainly make things difficult," he said.

A POLARIZED COUNTRY

The Supreme Court is expected to hand down a verdict within weeks on the charges that Bolsonaro and his allies plotted to overthrow democracy. It is widely expected to convict the former president.

Moraes' house arrest order cited a failure to comply with restraining orders he had imposed on Bolsonaro for allegedly courting Trump's interference in the case.

While domestically Moraes has received praise by some for defending Brazil's judicial independence, others have accused him of overreach.

The latest order drew mixed reactions, according to a Quaest poll based on social media posts, with 53% in favor and 47% against the arrest.

Newspapers that had written scathing editorials about the alliance between Bolsonaro and Trump also questioned Moraes' decisions.

"Moraes was wrong to order the arrest of the former president for communicating with supporters in a rally organized by the right," an editorial by Brazilian newspaper Folha de Sao Paulo said. "Brazil must acknowledge that Jair Bolsonaro has broad freedom to defend himself in court and to express himself wherever he chooses, including on social media."

Former Supreme Court justices, too, offered differing views regarding the decision.

"Alexandre de Moraes, in his ruling, not only upholds the country's sovereignty and independence but also the autonomy of Brazil's judiciary," said Carlos Ayres Britto, who left the Supreme Court bench in 2012.

But former Justice Marco Aurelio Mello disagreed. "My perspective would be different given the constitutional principle of presumed innocence," he said.