As Donald Trump cheered the passage of his self-styled, and officially named, Big Beautiful Budget Bill through Congress this week, long-sown seeds of doubt about the scale and sustainability of US borrowing from the rest of the world sprouted anew.
Trump's tax-cutting budget bill is expected to add at least $3 trillion (£2.2 trillion) to the US's already eye-watering $37tn (£27tn) debt pile. There is no shortage of critics of the plan, not least Trump's former ally Elon Musk, who has called it a "disgusting abomination".
The growing debt pile leaves some to wonder whether there is a limit to how much the rest of the world will lend Uncle Sam.
China is the largest foreign holder, but the vast majority of the debt is owed domestically.