The relationship between war and the global economy is one of history’s most consequential and under-examined connections. Wars destroy capital, displace populations and disrupt trade — but they also accelerate technological innovation, reshape political boundaries and create new economic orders that often persist for decades after the last shot is fired. Understanding this relationship is essential for comprehending how the world economy reached its current form and how present-day conflicts might shape its future.
World War I: The Death of Globalisation’s First Age
The First World War (1914-1918) is perhaps the most economically transformative conflict in modern history, in part because it destroyed a world that was in many ways more globally integrated than its successor. The pre-war era of the gold standard, free capital flows and relatively open trade — sometimes called the first age of globalisation — was shattered by four years of industrial warfare. Britain, the world’s leading creditor nation before the war, emerged as a debtor. The United States, the world’s largest debtor nation, emerged as its leading creditor. Germany was saddled with reparations payments so severe that John Maynard Keynes predicted they would lead to renewed conflict — a prediction that proved devastatingly accurate.
The war also triggered the Russian Revolution, which removed the world’s largest country from the capitalist economic system for seven decades and established a competing economic model that would shape global politics throughout the 20th century. The peace settlement’s failures created the economic and political conditions that produced the Great Depression and, ultimately, the Second World War.
World War II: The Blueprint for Modern Economic Order
The Second World War (1939-1945) destroyed more physical capital and killed more people than any conflict in history, yet it also laid the foundations for the most sustained period of economic growth the world has ever seen. The Bretton Woods conference of 1944 — held while the war was still raging — created the International Monetary Fund and the World Bank, established the dollar as the world’s reserve currency and set up the rules-based international economic order that still substantially governs the global economy today.
The Marshall Plan, through which the United States provided approximately $13 billion (equivalent to over $140 billion today) in reconstruction assistance to war-devastated Europe, represented a strategic investment in rebuilding democratic capitalist economies as buffers against Soviet communism. It was also one of the most economically successful foreign policy initiatives in history, helping to trigger the European economic miracle of the 1950s and 1960s and creating wealthy trading partners for American businesses.
The Korean War: The Military-Industrial Complex is Born
The Korean War (1950-1953) is often called “the forgotten war” in popular memory, but its economic consequences were enormous. The conflict permanently established the United States as a massive peacetime military spender, cementing what President Eisenhower would later famously call the “military-industrial complex” — the structural alliance between the defence industry and the permanent national security state. American defence spending, which had collapsed after World War II, surged again with Korea and never returned to pre-war levels, permanently reshaping the American economy and creating the backbone of what would become Silicon Valley through its investments in electronics and computing.
Vietnam War: Economic Overstretch and the End of Bretton Woods
The Vietnam War (1965-1975) is often discussed in political and moral terms, but its economic consequences were equally significant. Lyndon Johnson’s determination to fight the war without raising taxes — to maintain both “guns and butter” — led to massive deficit spending that overheated the American economy and generated inflation. The resulting strain on America’s dollar reserves eventually forced President Nixon to end the dollar’s convertibility to gold in August 1971 — the “Nixon shock” that ended the Bretton Woods system and ushered in the era of floating exchange rates that persists to this day.
Gulf War 1990-91: Oil Shock and the New World Order
Iraq’s invasion of Kuwait in August 1990 and the subsequent US-led coalition’s liberation of Kuwait had significant economic consequences beyond the immediate oil price shock. The war established the United States as the world’s unipolar military power and demonstrated America’s ability to project force globally. It also set a precedent for international coalition-building in response to aggression that would shape post-Cold War foreign policy. The oil market disruption was severe but relatively brief, with prices returning to pre-crisis levels once it became clear that the coalition would prevail.
Iraq War 2003: The Trillion-Dollar Mistake
Nobel Prize-winning economist Joseph Stiglitz co-authored “The Three Trillion Dollar War” in 2008, estimating the total economic cost of the US invasion of Iraq at over $3 trillion when long-term healthcare costs for veterans, interest on war debt and macroeconomic consequences were fully accounted for. The Iraq War contributed to the oil price spike of the mid-2000s, destabilised the Middle East in ways that reverberate to this day, and ultimately contributed to the conditions that created ISIS and the continuing regional chaos that followed the Arab Spring. As a case study in the hidden economic costs of military adventurism, it is without equal in recent history.
Afghanistan: Twenty Years and Two Trillion Dollars
The United States’ twenty-year engagement in Afghanistan, from 2001 to 2021, cost an estimated $2.3 trillion including war costs, reconstruction spending and long-term veterans’ care. The outcome — the Taliban returning to power within weeks of the final American withdrawal — has prompted searching questions about the return on investment of the world’s most expensive nation-building experiment. The economic and strategic lessons of Afghanistan continue to inform debates about military intervention and reconstruction in conflicts around the world.