Macroeconomic Schools

Every time prices lurch, economists stage the same argument about why — a quarrel older than the profession itself, running from the classical faith that markets always clear to today's fights over what a central bank can really do. The inflation surge after 2021, when US prices climbed at their fastest pace in forty years, set off the latest round. Monetarists blamed the pandemic flood of money; Keynesians blamed stimulus colliding with choked supply; Modern Monetary Theorists said the real limit was physical resources, not dollars; supply-shock analysts pointed at broken supply chains and war. No school saw the surge coming, and none has convinced the others in hindsight.

The quarrel has a bloodline. The classical tradition held that supply creates its own demand, so gluts cannot last; Keynes broke with it during the Depression, arguing that demand can fall short for years and that public spending can fill the hole. Milton Friedman's monetarist counter-revolution then put money back at the center — inflation, in his famous phrase, is always and everywhere a monetary phenomenon — and held that steady rules beat clever discretion. The next generation pushed the money view to its limit: if people form rational expectations and see policy coming, predictable policy changes nothing at all. Modern central banking is essentially a truce among these camps, the new Keynesian synthesis, which concedes that prices are sticky enough for interest rates to bite in the short run even if not the long. The living schools are less a menu of options than positions along this inherited fault line. Some still read every inflation as fundamentally monetary; some as a failure of demand management; the Austrians see the central bank itself as the disease, its cheap money breeding bad investment; Modern Monetary Theory insists that a country printing its own currency can never be forced to default, so the true ceiling is inflation, not the bond market. What is striking is how each was vindicated by one crisis and humiliated by the next. 2008 rehabilitated Keynes and baffled the monetarists, whose predicted inflation never arrived even as bank reserves exploded; 2021 flipped the board again, handing the round to the supply-side story and catching the Keynesians flat-footed on how fast prices would climb.