In 1964, the US historian Richard Hofstadter wrote an essay identifying the “paranoid style in American politics”. In the wake of Senator Joseph McCarthy’s crusade against communism, he described the use of “heated exaggeration, suspiciousness and conspiratorial fantasy” by the radical right.

By removing videos and podcasts by Alex Jones, the rightwing radio host and founder of Infowars, Apple, Facebook and YouTube last week limited the paranoid style on their platforms. Twitter held back, deciding that Mr Jones’ hostility to “the scientifically engineered lies of the globalists and their ultimate goal of enslaving humanity” falls within its rules.

Jack Dorsey, Twitter’s chief executive, declared in March that he was “committing Twitter to help increase the collective health, openness and civility of public conversation”. Last week, he said it was the job of journalists, not his platform, to “document, validate and refute” misinformation such as Mr Jones’ claim that the mass shooting of children at a school in Sandy Hook in 2012 was “a giant hoax”.