Speaking before an audience of senators in Brasília earlier this year, supreme court justice Alexandre de Moraes mused on one of the great conundrums of the internet age. “At the turn of the century, there was no social media. We were happy and didn’t know it,” he joked.

As if hoping to restore a modicum of that lost innocence, the judge last week banned X in Latin America’s largest nation, after the platform owned by Elon Musk refused to block accounts suspected of spreading hate messages or disinformation. 

The ruling, which affects roughly 20mn Brazilian users of the site, has pitched Moraes into the middle of a global debate about freedom of speech and how social media should be regulated. To his defenders, the 55-year-old magistrate is a hero who has protected democracy against a deluge of fake news. To detractors, he is guilty of censorship and unfairly targets conservatives.