One of the remarkable and heartening features of the global economy over the past couple of years has been the high ratio of rhetorical protectionist sabre-rattling to actual restrictions on international trade in goods and services.

But - as negotiators meet in Geneva for new talks on the Doha Round - the price of liberty is eternal vigilance. Protectionism has a miraculous ability to shape-shift, or at least an endless ability to exploit new issues to insinuate itself afresh into the public policy debate. Examples from the recent past range from spurious appeals to national security (the Dubai Ports World fiasco) to concerns over Asian currency manipulation and the safety of products made in China.