Remember Joe Sixpack? Having spent most of the postwar decades acting as the world’s consumer of last resort, America’s middle class was expected to play a more modest role after the 2008 crash. For a few years, US consumption went into hibernation. Now, with China’s growth slowing, Europe’s stalled and some of the early excitement fading from Japan’s “Abenomics”, prospects for global growth once again hinge on Joe’s appetite to spend. Is he feeling lucky?

The US middle class is hardly in an ideal condition to roar back as the engine of world growth. Median earnings have fallen by 5.4 per cent since the US recovery began. Unemployment remains closer to 8 per cent than 7 per cent. And households have at least temporarily stopped paying off their debt. Yet in the absence of other short-term sources of demand, hopes are once again pinned on the battered US consumer. Consumption accounts for roughly 70 per cent of US gross domestic product and about 16 per cent of global demand. Exporters everywhere are thus hoping the US consumer will do its bit for world prosperity.

Recent signs are that it is willing to help – but to what degree, and at what price, are open questions. In May, surging imports pushed the US trade deficit up by 12 per cent to $45bn, which was the largest jump in five years. Imports from China accounted for almost two-thirds of that. If it continues, the US-China deficit will exceed $300bn this year. Meanwhile, US exports fell. President Barack Obama’s goal of doubling exports in five years – always puzzling since it was a gross target – is beyond reach. Nor is business investment picking up. Last month the US added a healthy 195,000 jobs but it saw a continued decline in factory employment. Initial forecasts that the US recovery would be led by a manufacturing rebound now look badly misplaced.