Graydon Carter, the co-founder of Spy magazine and former editor of Vanity Fair, has said that President Donald Trump is 'mad,' and predicted the president's swift downfall.

Longtime Trump nemesis Carter, 70, made the remarks in a column on Friday for his new subscription newsletter, Air Mail, a publication targeted at 'well-heeled globalists.'

Citing 'the obvious decline in the president’s mental abilities,' Carter argues that Trump is no longer merely the 'tacky, self-regarding' developer of 1980s Manhattan, when the publisher famously dubbed him a 'short-fingered vulgarian.'

'Back then, if you overlooked the crassness and the pushy ambition, he even had a certain charm,' Carter fondly recalls of Trump.

Graydon Carter (left), the co-founder of Spy magazine and former editor of Vanity Fair, has said that President Donald Trump is 'mad'

'Given the powers granted him by dint of his current position, he is most certainly a real and present danger to the entire world—and as the week’s events have demonstrated, to himself,' Carter writes.

Carter predicts that the unfolding impeachment saga over Trump's contact with the president of Ukraine will prove the president's undoing, unlike prior attempts by Democrats.

'When presidents are undone, it’s generally by something simple and human that the public—and the headline writers—can grab onto: a break-in of an opponent’s headquarters; the remnants of a hasty tryst on an intern’s blue dress,' Carter opines.

'The Russian interference in our most recent presidential election has proven to be just as difficult, and Trump has not been hobbled. A one-sentence description is necessary,' the journalist continues.

Imagining a headline writer's crystalline summation of the Ukraine imbroglio, Carter writes: 'An American president asking a foreign leader to investigate his Democratic opponent, or lose almost $400 million in military aid'.

Carter is seen in 1988, when he was running Spy magazine, which dubbed Trump a 'short-fingered vulgarian.' The satrical magazine folded in 1998

Trump pushed Ukrainian President Volodymyr Zelenskiy to investigate whether Joe Biden had pressured the country to drop an investigation into an energy company that his son, Hunter, served on the board of.

'It’s a story that anyone can understand and should be repulsed by,' Carter inveighs.

The eminent journalist, who has been criticized in recent months for allegedly burying reporting on sexual misconduct allegations against Jeffrey Epstein in 2003, predicts that Trump will soon be abandoned by his political allies.

'My guess is that if and when Ukraine-gate heads toward its rightful conclusion, Trump’s enablers—even Senate majority leader Mitch McConnell, House minority leader Kevin McCarthy, and the president’s Fox News cheerleading squad—will eventually scatter the way cockroaches do when the kitchen lights go on,' Carter writes.