Years before he ran for office, Donald Trump cultivated a style of speaking that was brash, blunt, and (in his opinion) totally honest. “I tell it like it is,” Trump said repeatedly on the campaign trail in 2016, breathing new life into a slogan used by politicians dating back to Richard Nixon, and hinting at a powerful rhetorical mode first described by the ancient Greeks.

In The Constitution of Athens, Aristotle tells a story of the tyrannical ruler Pisistratus, who went into the countryside to observe the farms upon which he imposed taxes. Seeing a farmer working a dry piece of ground, Pisistratus approached the man to ask what the land produced for him. Not recognizing Pisistratus, the man replied: “Aches and pains! And that’s what Pisistratus ought to have his tenth of!” As king, Pisistratus had the prerogative to kill the farmer on the spot, but he was so impressed with the man’s frank speech – his parrhesia – that he exempted the farm from taxation.

Since the beginning of Trump’s political career, nothing has bothered the establishment more than the way he speaks, and what he says. Whether the criticism is valid is irrelevant because Trump’s parrhesiastic style of speaking helped put him in the Oval Office.

In a series of lectures titled Fearless Speech, leftist French philosopher Michel Foucault derives five criteria that must be met to classify speech as parrhesiastic: