Musk vs. Brazil Supreme Court: five things to know

X owner Elon Musk is under investigation in Brazil after he accused a Supreme Court judge of censoring social networks, calling him a "dictator" and vowing to disobey rulings blocking users found to be spreading disinformation.

Here are five things to know about the billionaire's beef with powerful, polarizing Justice Alexandre de Moraes.

- Musk attacks -

Musk went on the attack at the weekend against Moraes, who has waged a crusade against disinformation -- especially attempts by far-right supporters of ex-president Jair Bolsonaro to discredit the electoral system ahead of Brazil's 2022 elections.

Moraes has "betrayed the constitution" and "should resign or be impeached," the Tesla and SpaceX boss wrote on X, the former Twitter, threatening to defy court orders blocking users.

The flare-up came after US journalist and activist Michael Shellenberger last week accused Moraes of a "sweeping crackdown on free speech," in a report based on the "Twitter Files," a cache of internal documents Musk released in 2022 after buying the company.

Shellenberger said the files showed Moraes "sought to censor... sitting members of Brazil's Congress" and "weaponize Twitter's content moderation policies against supporters of then-president @jairbolsonaro."

Bolsonaro narrowly lost the 2022 elections to veteran leftist Luiz Inacio Lula da Silva.

- Supreme Court response -

Moraes, who is also head of Brazil's Superior Electoral Tribunal, responded Sunday by ordering fines of 100,000 reais (around $20,000) a day for any blocked account that X reactivates -- which has not happened yet.

Users blocked by Moraes include figures like far-right ex-congressman Daniel Silveira, who was sentenced to nine years in prison in 2022 on charges of leading a movement to overthrow the Supreme Court.

Accusing Musk of "criminal instrumentalization" of X, Moraes placed the South Africa-born mogul under investigation for crimes including conspiracy and obstruction of justice.

Moraes also added Musk to an ongoing "Digital Militias" probe, which is investigating accusations that Bolsonaro and his inner circle illegally used state resources to orchestrate online disinformation campaigns during his presidency (2019-2022).

- Musk and Bolsonaro -

Musk has something of a bromance with Bolsonaro, the politician dubbed the "Tropical Trump."

Bolsonaro, who has himself had numerous posts removed from social media for spreading disinformation, celebrated Musk's takeover of Twitter in 2022 and gave him a medal for his "service to Brazil" when the billionaire made a high-profile visit that year.

Bolsonaro reposted a video of that meeting Saturday on X.

Musk "is our salvation," he said in another video Sunday. "Our democracy is under threat."

Amid the row, Brazil's far right has rallied around Musk and doubled down on its hatred for Moraes. Hardline conservative lawmakers launched a manifesto backing the call for Moraes's impeachment.

- Cage fight? -

Musk put the spat in dramatic terms.

"We will probably lose all revenue in Brazil and have to shut down our office there," he wrote Saturday. "But principles matter more than profit."

Besides pledging to reinstate blocked accounts, he vowed a "full data dump" of Moraes's court orders.

He has not followed through on either yet.

Online, some rooted for the row to go to the ring, like Musk's aborted plan for a cage fight with Meta boss Mark Zuckerberg last year.

"Musk wanted to get in the octagon with Zuckerberg. Now he's going with Xandao (Moraes's nickname) instead. I'd pay to see that fight," one X user wrote.

Moraes looks unlikely to face impeachment -- or slow his disinformation crackdown.

Supreme Court Chief Justice Luis Roberto Barroso issued a statement Monday supporting Moraes's rulings.

- 'Censorship' vs. regulation -

Senate president Rodrigo Pacheco, whose chamber would preside over any impeachment case, meanwhile rejected the "censorship" label. He called on lower-house lawmakers to pass a bill regulating social networks, as the Senate did in 2020.

Brazil is part of a growing international debate about the limits of free speech on social media, where some say allowing a free-for-all endangers democracy.

"Freedom of speech is one thing. Coordinated, financed attacks on democracy itself are another," Brazilian digital rights expert Estela Aranha told AFP.

She said it is "urgent and important" to regulate social media, but she is not holding out hope for that to happen soon in deeply polarized Brazil.