From Prof Jagdish Bhagwati.

Sir, In my article "America's bipartisan battle against free trade" (April 9) on US trade policy I described how multilateral free trade was being undermined in the United States by free traders who forgot that preferential trade agreements (PTAs) were creating a spaghetti bowl of preferences that were multiplying continually and by protectionists who were using in new ways the old trick of alleging "unfair trade" to cripple free trade.