On January 8, 2023, thousands of Bolsonaro supporters stormed Brazil's Three Powers Plaza in Brasília, breaking into the Congress, the presidential palace, and the Supreme Court itself. The Brazilian justice system spent two years building the case for accountability. In September 2025, the Supreme Federal Tribunal — the STF — convicted former President Jair Bolsonaro on five counts including attempted coup d'état and sentenced him to 27 years and three months in prison. Many observers called it a landmark for Latin American democracy. That landmark is now the subject of the most consequential constitutional dispute in Brazil in decades.

What the Dosimetry Law does

The legislation at the centre of the dispute is Law 15.402/2026, known as the Dosimetry Bill. Passed by Congress in December 2025 and promulgated in May 2026 after President Lula's veto was overridden, it changes how sentences are calculated for crimes including attempted coup d'état and the violent abolition of democratic order. Under the new rules, a defendant convicted of multiple offences arising from the same context serves only the sentence for the most serious crime rather than the cumulative total. It also introduces sentence reductions of between one third and two thirds for individuals convicted as part of a crowd — provided they were not organisers or financiers — and lowers the threshold for progression from closed to semi-open prison regimes.

The practical effect on Bolsonaro's case is dramatic. Pre-law projections placed his progression to a semi-open regime at around 2033. Under the Dosimetry Law, legal analysts estimated his time in a closed regime could fall to as little as two years and four months, with semi-open progression possible as early as 2028. A 27-year sentence, in effect, could become something closer to a suspended one.

The three-way collision

What makes the Dosimetry episode constitutionally extraordinary is the sequence of institutional collisions it produced in the space of two weeks. Lula issued a full veto in January 2026, calling the bill an affront to democratic accountability. On April 30, the lower house overrode the veto 318 to 144; the Senate followed 49 to 24. On May 8, Senate President Davi Alcolumbre formally promulgated the law after Lula allowed the deadline to lapse without further action. On May 9 — one day later — STF Justice Alexandre de Moraes, the rapporteur of the Bolsonaro prosecution and the most controversial figure in Brazilian judicial politics, suspended the law's application pending a full plenary review. His suspension froze not only Bolsonaro's case but all 190-odd related cases from the January 8 attacks.

The timing was not lost on anyone. Senator Flávio Bolsonaro, the former president's eldest son and a declared candidate for the October 2026 presidential election, called Moraes' decision "judicial interference in the sovereignty of Congress." Left-wing parties including PSOL-Rede and the Brazilian Press Association filed constitutional challenges — ADIs 7966 and 7967 — arguing the law was designed to selectively benefit those convicted of attempting to destroy institutional order, and that it was therefore unconstitutional on its face. STF Justice Gilmar Mendes said publicly that a plenary verdict would come "within a few days." As of late June 2026, that verdict is still pending.

The deeper constitutional question

The STF's decision will turn on a question that goes well beyond Bolsonaro's sentence: can a democratically elected Congress pass a law that retroactively reduces the punishment for an attempt to overthrow democracy itself? Left-wing parties argue that permitting such a law would hollow out the entire framework of democratic self-protection that Brazil's 1988 Constitution was designed to create. The Brazilian Press Association's brief notes that the law was crafted to benefit a specific class of defendants — those convicted of anti-democratic crimes — and that this selective application violates constitutional equality principles.

The defence of the law rests on a different principle: that retroactive sentence reduction is a standard feature of Brazilian criminal law, that the January 8 participants included many ordinary citizens swept up in events whose severity they may not have understood, and that it is the role of an elected legislature — not an appointed court — to set sentencing policy. Senator Alessandro Vieira, one of the centrist bloc votes that proved decisive, said it was necessary to distinguish between those who "organised the riot" and those who were "used as pawns."

A court under pressure

The Dosimetry battle also arrives at a moment when the STF's own institutional position is under unusual strain. In April 2026, the Senate rejected Lula's Supreme Court nominee Jorge Messias by 42 votes to 34 — the first time in 132 years that Brazil's Senate had blocked a presidential appointment to the court. Critics from both left and right have argued that the STF, and Moraes in particular, has expanded its powers far beyond the traditional role of a constitutional tribunal, acting as a political arbiter, a co-legislator, and — in the Bolsonaro prosecution — as both prosecutor and judge in all but name. The plenary hearing on the Dosimetry Law will be watched not only for its verdict on Bolsonaro's sentence, but as a test of whether Brazil's Supreme Court retains the political legitimacy to act as the final word on questions this fundamental — and this politically charged — in the months before a presidential election.

Camila Ferreira

Articles

The Coup That Keeps Coming Back: Brazil's Constitutional Showdown Over the Dosimetry Law