Monetarism

For much of the mid-twentieth century, Keynesian demand management reigned almost unchallenged. Then, from the 1950s onward, an economist at the University of Chicago mounted a counter-revolution. Milton Friedman argued that the key to understanding inflation and the business cycle lay not in government spending but in something more fundamental: the quantity of money. By the 1970s, as Keynesian remedies seemed to falter against stubborn inflation, his ideas — collectively known as monetarism — moved from the academic fringe to the centre of policy, with consequences felt sharply in 1980s Britain.

Money at the centre

Monetarism holds that changes in the money supply are the main driver of changes in the price level, and in the short run of output and employment too. Its most famous slogan, from Friedman, is that “inflation is always and everywhere a monetary phenomenon”. By this he meant that sustained, ongoing inflation is ultimately caused by the money supply growing faster than the economy’s output of goods and services — not by greedy trade unions, monopolistic firms or one-off shocks like oil price rises, however much those might feature in the headlines. Control the growth of money, the argument runs, and you control inflation.

The intellectual backbone of this view is the quantity theory of money, an old idea Friedman revived and refined. It is often written as MV = PT (or MV = PY): the money supply multiplied by its velocity of circulation equals the price level multiplied by the volume of transactions or output. Velocity is simply the average number of times a unit of money is spent in a given period. The monetarist case rested on the assumption that velocity is relatively stable. If that holds, then an increase in the money supply translates fairly predictably into higher nominal spending, and — once output is at capacity — into higher prices.

The critique of Keynesianism

From this foundation, Friedman launched a sustained critique of Keynesian activism. Keynesians believed governments could fine-tune the economy, boosting demand in slumps and restraining it in booms. Friedman thought this both overconfident and dangerous. His core objection was that policy works with “long and variable lags”: the effects of a change in policy on the real economy take an uncertain and changeable amount of time to appear. A stimulus enacted to fight today’s recession might only take full effect once recovery is already underway, adding fuel just as the economy overheats. Far from smoothing the cycle, well-meaning intervention could amplify it.

Friedman also challenged the Keynesian idea of a stable trade-off between inflation and unemployment. He argued there is a “natural rate of unemployment”, set by real features of the labour market. Governments could push unemployment temporarily below it by expanding demand, but only at the cost of accelerating inflation; over time, workers would come to expect the higher inflation and unemployment would return to its natural level, leaving the economy worse off. This insight, developed around the same time by Edmund Phelps, helped explain the stagflation of the 1970s — simultaneous high inflation and high unemployment — that had so embarrassed the simple Keynesian story.

Rules over discretion

If activist fine-tuning was unreliable, what should policymakers do instead? Friedman’s answer was to favour rules over discretion. Rather than central banks and governments constantly intervening, he argued for a steady, predictable expansion of the money supply at a fixed rate roughly in line with the economy’s long-run growth. This monetary “rule” would, he hoped, provide a stable backdrop, removing a major source of instability that he believed badly managed money had itself created.

That belief drew heavily on history. In A Monetary History of the United States, written with Anna Schwartz, Friedman made his most influential historical case: that the Great Depression of the 1930s was not proof of capitalism’s inherent instability, as many concluded, but the result of a catastrophic monetary policy failure. The US Federal Reserve, he argued, had allowed the money supply to collapse by roughly a third, turning a recession into a depression. The lesson was that the central bank’s job was, above all, not to let money go badly wrong.

The 1980s and after

Monetarism’s biggest practical test came as Western economies struggled with high inflation in the late 1970s and early 1980s. In the United Kingdom, the Thatcher government, confronting double-digit inflation, adopted monetarist-influenced policies. It set explicit targets for the growth of the money supply and made the conquest of inflation its overriding priority, ahead of maintaining full employment. The result was a period of tight monetary and fiscal policy: inflation fell substantially, but unemployment rose to very high levels and large parts of industry contracted. The episode remains deeply controversial, defended by some as necessary medicine and condemned by others as needlessly painful.

In practice, strict monetarism proved harder to operate than the theory suggested. The relationship between the various measures of money and inflation turned out to be less stable and predictable than Friedman had hoped, and velocity was not the reliable constant the simple theory required. Money supply targets were repeatedly missed or redefined. Over the following decades most central banks, including the Bank of England, quietly shifted away from targeting the money supply directly and towards targeting inflation itself, using interest rates as the main lever. Yet monetarism’s deeper legacy endured: the conviction that controlling inflation is a central duty of monetary policy, the scepticism about fine-tuning, and the idea of the natural rate all remain woven into mainstream economics today.