Brazil's Supreme Court decision to place former president Jair Bolsonaro under house arrest has heightened concerns within President Luiz Inácio Lula da Silva's government that Donald Trump, a close ideological ally of the far-right leader, will use the move to justify further economic retaliation against Latin America's largest economy.

The court order, issued on August 4 by Justice Alexandre de Moraes, came just two days before the implementation of 50% tariffs on Brazilian goods announced by the US president last week. Members of Lula's Workers' Party administration privately acknowledged the timing could "exasperate" Trump and provide ammunition for his campaign against what he terms Brazil's "witch hunt" of Bolsonaro.

Justice Moraes cited Bolsonaro's "repeated failure" to comply with court restrictions imposed during his trial for allegedly plotting to overturn his 2022 electoral defeat. The former president had been banned from social media and required to remain at home between 7pm and 6am, but appeared in video calls during the August 3 demonstrations by his supporters, which drew thousands of people across multiple cities.

"Good afternoon Copacabana, good afternoon my Brazil, a hug to all," Bolsonaro said in footage posted by his son Senator Flávio Bolsonaro on social media before being deleted. "It's for our freedom, we're together."

The breach prompted Moraes to ramp up restrictions, confining Bolsonaro to his Brasília residence and prohibiting mobile phone use except for authorised legal consultations. The justice warned that any further violations would result in detention, declaring that Brazil's judiciary would not allow a defendant to "treat it like a fool" due to his "political and economic power".

The US State Department condemned the house arrest within hours, with its Western Hemisphere bureau posting on social media: "Minister Alexandre de Moraes, already sanctioned by the United States for human rights violations, continues to use Brazilian institutions to silence the opposition and threaten democracy. Let Bolsonaro speak!"

The statement warned that Washington would "hold accountable all those who collaborate with or facilitate sanctioned conduct," raising the prospect of expanded sanctions beyond the 50% tariffs taking effect on August 6.

Within Lula's administration, officials admitted the arrest could complicate efforts to negotiate with Trump, though they argued Moraes had little choice given Bolsonaro's brazen defiance of court orders. Unlike previous judicial decisions against the former president, government ministers notably avoided public statements supporting the Supreme Court's action.

According to Folha de Sao Paulo, Workers' Party president Edinho Silva attempted to contextualise the decision, noting it stemmed from violations of court orders in an investigation into an alleged coup plot that "aimed to take the lives of leaders of fundamental institutions of the Republic: Lula, Alckmin, and Alexandre de Moraes".

Some Bolsonaro allies quoted by Estadao suggested the social media post was a calculated provocation designed to trigger a stronger response from Moraes and draw further US intervention. Eduardo Bolsonaro, the former president's congressman son who has relocated to Washington to lobby in favour of his father, called Moraes "an out-of-control psychopath".

The diplomatic standoff has created an unprecedented situation where the US is sanctioning a Brazilian Supreme Court justice whilst threatening punitive trade measures over domestic legal proceedings. Trump has banned Moraes from entering the United States and frozen any US assets.

Bolsonaro faces up to 40 years in prison if convicted of plotting to cling to power after losing the 2022 election. Prosecutors allege he and co-conspirators attempted to overturn the result in a plot that failed only because the military refused to participate.

The case draws parallels with the January 6, 2021 attack on the US Capitol, particularly given that Bolsonaro supporters stormed Brazil's congress in January 2023 following Lula's inauguration.

Despite being barred from running for office until 2030, Bolsonaro hopes to mount a Trump-style political comeback in Brazil's 2026 presidential election, banking on continued US pressure to alter the trajectory of his legal troubles.

However, some within his own movement worry that Trump's aggressive tactics may be backfiring, potentially rallying Brazilian public opinion behind Lula's government whilst compounding Bolsonaro's legal difficulties.