The Interwar Era

A Peace to End All Peace

The armistice of November 1918 ended the fighting. The Treaty of Versailles, signed in June 1919, was supposed to end the war. It did neither. Instead, it produced a settlement so economically punitive that it poisoned European politics for a generation. Germany was saddled with reparations obligations that, in their original formulation, amounted to roughly 260 percent of its 1913 GDP. The Allies had financed the war largely through borrowing — from each other and from American banks — and reparations were the mechanism by which those debts were supposed to be repaid. The logic was circular and, as one young British Treasury official recognized immediately, catastrophic.

John Maynard Keynes had attended the peace conference as a representative of the British Treasury. He resigned in despair and published The Economic Consequences of the Peace in 1919, a book that made him famous and made the treaty infamous. Keynes argued that the reparations burden was both unpayable and destructive — that squeezing Germany would wreck the European economy on which Allied prosperity also depended. The book was polemical, personal (its portrait of Woodrow Wilson is devastating), and substantially correct. It also established Keynes as a public intellectual of the first rank, a position he would hold for the rest of his life.

Hyperinflation and the Trauma of Money

The reparations crisis came to a head in Germany in 1923. Unable to meet its obligations, the Weimar government resorted to printing money. The result was one of history’s most spectacular episodes of hyperinflation. Prices doubled every few days. Workers collected wages in wheelbarrows and spent them within hours before the money lost further value. A loaf of bread that cost 250 marks in January 1923 cost 200 billion marks by November. The German mark, once one of the world’s hardest currencies, became worthless.

The hyperinflation destroyed the savings of the German middle class and scarred the national psyche in ways that would shape policy for a century. The Reichsbank’s loss of credibility became a foundational story for central bankers everywhere — the cautionary tale invoked whenever monetary expansion is proposed. Stabilization came in late 1923 with the introduction of the Rentenmark and, eventually, the Dawes Plan, which restructured reparations and channeled American loans to Germany. For a few years, it seemed to work. But the prosperity of the late 1920s was built on American credit, and when that credit evaporated, the entire structure collapsed.

The Crash and the Spiral

The Wall Street crash of October 1929 was not, by itself, the Great Depression. Stock market corrections had happened before without triggering economic catastrophe. What made this time different was the chain of failures that followed — a cascade of bank runs, credit contractions, tariff wars, and policy mistakes that turned a financial panic into the worst economic disaster in modern history.

The numbers remain staggering. Between 1929 and 1933, U.S. industrial production fell by nearly half. Unemployment reached 25 percent. International trade collapsed by two-thirds. The human cost — hunger, displacement, despair, the erosion of faith in democratic institutions — cannot be captured in statistics alone.

In 1931, the crisis spread to Central Europe when the Creditanstalt, Austria’s largest bank, failed. The contagion raced through the European banking system, forcing country after country off the gold standard. Britain, the gold standard’s historic champion, abandoned it in September 1931. The international monetary system that had underpinned the prewar liberal order was dead.

The Gold Standard Trap

The gold standard was not merely a technical arrangement; it was an ideology. Its defenders — and they were many, occupying the commanding heights of central banking and treasury departments — believed that fixing currencies to gold imposed discipline, prevented inflation, and facilitated international trade. They were not entirely wrong in theory. In practice, during the Depression, the gold standard became a straitjacket. Countries that clung to gold were forced to raise interest rates and cut spending precisely when their economies were collapsing, deepening the downturn. Countries that left gold early — Britain in 1931, the United States in 1933 — recovered faster. The correlation was unmistakable: the gold standard transmitted and amplified the Depression.

Irving Fisher, who had lost his personal fortune in the crash, produced his debt-deflation theory in 1933. The mechanism was cruel in its simplicity. When prices fall, the real burden of debt rises. Debtors cut spending and sell assets to meet their obligations, driving prices down further, which increases the real burden of debt still more. The result is a self-reinforcing spiral in which the very attempt to pay off debts makes them harder to pay. Fisher’s theory was largely ignored at the time — he had been discredited by his own ruinous optimism before the crash — but it would be rediscovered decades later as a key to understanding financial crises.

The Hayek-Keynes Debate

The Depression provoked the most consequential intellectual confrontation in the history of economics. In one corner stood Friedrich Hayek, a young Austrian economist who had arrived at the London School of Economics in 1931. Hayek argued that the Depression was the inevitable consequence of the credit boom of the 1920s — that artificially low interest rates had distorted the structure of production, directing investment toward projects that were unsustainable once credit tightened. The cure, painful as it was, was to let the liquidation run its course. Government intervention would only delay the necessary adjustment and sow the seeds of the next crisis.

In the other corner stood Keynes, who found this prescription not merely wrong but morally intolerable. The economy was not self-correcting in any useful timeframe. People were starving, factories were idle, and the orthodox remedy — balance budgets, maintain gold parity, wait — was making everything worse. The debate between Hayek and Keynes, conducted through books, articles, letters, and public lectures, was the founding argument of modern macroeconomics. Their disagreements about the nature of money, the role of the state, and the stability of market economies remain unresolved today.

The Keynesian Revolution

Keynes’s General Theory of Employment, Interest and Money, published in 1936, was the most influential economics book of the twentieth century. It was also, by near-universal agreement, one of the most difficult. The prose was brilliant in flashes and obscure in stretches. The formal apparatus was incomplete. Different readers came away with different interpretations, and the arguments over what Keynes “really meant” have never ended.

But the core message was clear enough to reshape the world. Market economies, Keynes argued, do not automatically tend toward full employment. They can settle into equilibrium — a stable state — with massive unemployment, because aggregate demand can be chronically insufficient to employ all available resources. The culprit was uncertainty. Investment depends on expectations about the future, and those expectations are inherently unstable — driven by what Keynes called “animal spirits” rather than cool calculation. When confidence collapses, private spending collapses with it, and no mechanism in the price system reliably pulls it back.

The policy implication was revolutionary: when private demand fails, the government must step in. Deficit spending, far from being irresponsible, was the appropriate response to a depression. The government should borrow and spend, putting money into the economy, creating demand where the private sector could not. Balanced budgets during a slump were not fiscal virtue; they were fiscal suicide.

The Legacy of Catastrophe

The interwar era ended where it began — in war. The economic catastrophe of the 1930s did not cause the Second World War in any simple sense, but it created the conditions in which fascism and militarism could flourish. Mass unemployment fed political extremism. The collapse of international trade fostered beggar-thy-neighbor nationalism. The failure of democratic governments to provide basic economic security discredited democracy itself in the eyes of millions.

The economists who lived through this period — Keynes, Hayek, Fisher, Schumpeter, the young Paul Samuelson — carried its lessons with them for the rest of their careers. They disagreed profoundly about what those lessons were. But they shared one conviction: the interwar catastrophe must never be repeated. The postwar institutions they built — Bretton Woods, the welfare state, the commitment to full employment — were designed as bulwarks against the return of the 1930s. Whether those bulwarks would hold was the great question of the decades that followed.