World War II boosted US economic fortunes, and after victory, Washington was in pole position to lead the world. Strong, agile and confident, its industries could now take on foreign competitors and showcase capitalism to thwart the Soviets' communist influence. For these reasons, as well as the memory of the Smoot Hawley years, America would now be a cheerleader for open markets. In theory, anyway.

The Americans and 22 other countries met in Geneva in 1947. Together, they negotiated the General Agreement on Tariffs and Trade (GATT). The negotiations were difficult. Washington disliked Britain’s so-called preference system, which lowered trade barriers for Commonwealth members and raised them for others. Meanwhile, Britain still resented America's pre-war policy.

Nevertheless, the talks succeeded in reducing tariffs, and the GATT would become a major part of the post-war order. Over a further seven rounds of negotiations, it significantly lowered trade barriers before the World Trade Organisation replaced it in 1995. The triumph of free trade? No. Even in the American age, not everyone was playing the same game…

A history of tariffs: do they work and who do they hurt?