For Donald Trump, tariffs are a “magic pudding”, an endlessly expanding source of revenue for whatever comes to his mind.

Last month they were going to fund a $US2000 ($3000) “tariff dividend” for US households, while also paying down America’s “enormous” debt.

US President Donald Trump’s latest plan does not add up.Credit: AP

Then, late last Thursday, he decided they could also fund the abolition of personal income taxes in the US.

“Over the next couple of years, I think we’ll substantially be cutting and maybe cutting out completely, but we’ll be cutting income tax,” he told members of the US military in a video call.

“Could be almost completely cutting it because the money we’re taking in is going to be so large.”

Trump has floated the idea of using tariff revenue to eliminate income taxes before, during last year’s election campaign and, again, after his “Liberation Day” tariffs on the rest of the world were unveiled in early April.

He has referred longingly to the period in the late 19th century when there were no income taxes in the US and government was funded by tariff revenue, though he overlooks the fact that, back then, government spending was less than 2 per cent of US GDP while today it exceeds 22 per cent.

He may, of course, not have any new tariff revenues of substance if the US Supreme Court rules the April 2 tariffs illegal – and emphasising their revenue-raising potential might not be the best strategy ahead of that decision, given the administration’s lawyers argued they weren’t primarily intended to raise revenue and would be most effective if there were absolutely no revenue from them.

His Thanksgiving Day comments to the military were, however, greeted deliriously (and taken very seriously) by his MAGA followers on social media. And they weren’t........

© The Sydney Morning Herald