America's trade gap mushroomed last year largely because the US economy grew rather faster than its trading partners economies. While Americans bought record amounts of imported consumer goods, notably cars and electronic products, US exporters had a hard time selling into sluggish markets abroad.
The trade gap in manufactured products has been widening for sometime - partly due to the growing significance of imports from low wage developing nations, notably China. That's an established trend. More surprising were figures showing that last year imports of farm products into the US exceeded the value of agricultural exports for only the second time ever.
Worryingly for policy makers, the deficit in trade of all types of goods showed an unexpectedly large increase in the final month of last year. Economic theory suggests that ultimately excessive trade deficits are corrected by currency devaluation. A sudden slump in the value of the US dollar would probably have a destabilising impact on the entire world economy.
It hasn't happened yet - though the dollar has declined modestly in value in recent months - but it still might. America's trade gap is clearly huge, but nobody really knows whether it's unsustainable.