Alexandre de Moraes: Brazilian judge in showdown with far-right
In the 56-year-old judge's sights is far-right ex-president Jair Bolsonaro, accused of plotting to cling onto power despite his failed October 2022 re-election bid.
A showdown with tech titan Elon Musk has meanwhile put Moraes in the crosshairs of US President Donald Trump's administration, which has hinted it could deny visas to foreign officials who threaten US nationals or residents over social media posts.
Moraes shut down Musk's X network in Brazil, one of its largest markets, for 40 days for failing to tackle disinformation, mostly shared by supporters of Bolsonaro.
Musk reacted with fury at the time, branding Moraes an "evil dictator cosplaying as a judge" and accusing him of "trying to destroy democracy in Brazil."
Bolsonaro also has called Moraes a "dictator," while his son Eduardo, an MP, has lobbied for US sanctions against the "totalitarian" judge.
Moraes ordered that the younger Bolsonaro be placed under investigation for alleged obstruction of justice.
Hero or villain?
Known by his nickname, "Xandao," Moraes looms large over a deeply divided Brazil.
The immensely powerful judge, who previously headed the Superior Electoral Tribunal (TSE), is hated by the far right, which accuses him of censorship and abuse of office.
To others, the muay thai aficionado is a hero on a mission to save Brazil's young democracy.
There was little in Moraes's background to hint he would become a thorn in the side of conservatives.
The constitutional law expert worked as a Sao Paulo state prosecutor, and went on to become state security secretary. Known as a hardliner, he drew criticism from left-wing activists, who accused him of repressing social movements.
He served as justice minister under center-right ex-president Michel Temer, who named him to the Supreme Court in 2017.
"He's a political animal," constitutional law expert Antonio Carlos de Freitas told AFP.
Supreme Court insiders call him a pragmatist.
But his pursuit of Bolsonaro and Musk's X showed a steelier side.
Moraes has presided over a slew of cases targeting Bolsonaro, barring the so-called "Trump of the Tropics" from running for office until 2030 over his attempts to discredit the electoral system.
But it is the coup investigation that threatens to definitively torpedo Bolsonaro's political comeback bid.
The 70-year-old former army captain risks up to 40 years in prison if convicted of plotting to prevent leftist Luiz Inacio Lula da Silva from taking power.
Prosecutors say the plot included a plan to arrest and even assassinate Lula, his vice president Geraldo Alckmin and Moraes.
'Political animal'
Moraes was an omnipresent figure during the polarizing 2022 election campaign, aggressively using his rulings to fight election disinformation on social media.
That included blocking the accounts of some prominent conservative figures, leading to his standoff with Musk, who has been accused of turning his social media platform into a megaphone for right-wing conspiracy theories.
The married father of three gives few interviews, and rarely posted on his X account, where he had a million followers, before closing it in February.
"Freedom of expression doesn't mean freedom of aggression," he has said.
"It doesn't mean the freedom to defend tyranny."
Still two decades away from the mandatory retirement age for judges in Brazil of 75, Moraes has been cited as a possible future candidate for president.
He has never discussed any such ambitions publicly.