For 20 years, and especially in the past decade, rapidly rising debt has allowed America's consumption growth to exceed economic growth, with a concomitant rise in the country's trade deficit. One consequence of this too-rapid growth in American consumption has been that the non-US global economy was able to grow faster than non-US global consumption. This was especially true for Asia, the main beneficiary of the US consumption boom, and for China in particular.

While Chinese consumption was growing at an impressive 9 per cent a year over the past few years, Chinese gross domestic product growth substantially outpaced it, clocking in at 10 per cent to 13 per cent annually. China was able to do this in large part because as it poured resources and cheap financing into manufacturing, and in so doing produced many more goods than Chinese households and businesses were able to consume, the balance was exported abroad, where much of it was absorbed by US consumers.

But everything has changed. Whether America likes it or not, US debt levels will decline over the next several years. As a result American consumption will grow substantially slower than the US economy, and so the trade deficit will decline. For the rest of the world, even ignoring the possibility of a decline in global investment, a contraction in the US trade deficit will bring with it a period in which economic growth will be less than consumption growth.