The late Canadian economist Harry Johnson, who came at the subject from the Monetarist persuasion, was correct when he wrote in 1969 (reference below) that “The adoption of flexible exchange rates would have the great advantage of freeing governments to use their instruments of domestic policy for the pursuit of domestic objectives, while at the same time removing the pressures to intervene in international trade and payments for balance-of-payments reasons.” How does this square with those who believe that even currency-issuing governments are constrained in their fiscal flexibility by an alleged balance of payments constraint. So-called progressive economists, particularly, are enamoured with the idea that Modern Monetary Theory (MMT) is flawed because it doesn’t recognise the fiscal limits imposed by the need to maintain a stable external balance. In this blog, we trace the arguments.