This week marked a striking milestone in the long commercial dance between China and the US. Jack Ma, founder of Alibaba, the e-commerce group, addressed the Economic Club of New York and used that occasion to reveal that his company is expanding so fast that “this year possibly we [at Alibaba] are going to be bigger than Walmart.”

The American audience did not recoil in horror, as you might expect. Instead they cheered his speech as inspirational. The reason? As Mr Ma described his wild ambitions for Alibaba, he also presented a startlingly charismatic dream about how global trade could create a shining future for everyone, including Americans. “In 10 years there will be half a billion people who are middle class [in China],” he observed. “[They] are hungry for American [goods] — we will help small businesses in America to go to China and sell.”

As a piece of public relations, it was brilliant. Mr Ma, after all, wants to persuade as many people as possible to use his platform to trade and hopes that within a few years Alibaba will draw 40 per cent of its revenues from outside China, compared to 2 per cent now.