It is clear after the Brexit vote and Donald Trump’s victory in the Republican presidential primaries that voters are revolting against the relatively open economic policies that have been the norm in the US and Britain since the second world war.

Populist opposition to international integration is on the rise in much of continental Europe and has always been the norm in Latin America. The question now is what should be the guiding principles of international economic policy? How should those of us — who believe that the vastly better performance of the global system after the second world war than after the first world war is largely due to more enlightened economic policies — make our case?

The mainstream approach starts with a combination of rational argument and inflated rhetoric about the economic consequences of international integration. Studies are produced about the jobs created by trade agreements, the benefits of immigration and the costs of restrictions. In most cases the overall economic merits are clear. But there is a kind of Gresham’s Law of advocacy whereby bolder claims drive out more prudent ones. Over time this has caught up with the advocates of integration.