“Why do great nations fail?” a Chinese professor asks an auditorium of attentive students in Beijing in 2030. “The ancient Greeks, the Roman Empire, the British Empire and the United States of America. They all made the same mistakes. They turned back on the principles that made them great.”

The slickly produced advertisement, which was put up last weekend by Citizens Against Government Waste, an independent group, has been described by some pundits as the midterm “advert of the season”. Six months ago many had been expecting that China – or fear of China – would play a larger role in the US midterm elections.

But until last week resentment of China’s economic prowess was the dog that had largely failed to bark. Furthermore, the CAGW advert, which targets President Barack Obama’s allegedly excessive spending, sidesteps the widespread view across the US that jobs continue to be exported to east Asia – one that also features in ever stronger anti-trade sentiments. A recent NBC/WSJ poll showed that 53 per cent of Americans think free trade has been bad for the country.