In February 1945, Franklin Roosevelt, Winston Churchill, and Josef Stalin met at Yalta, in the Crimea, to plan the postwar world. They agreed on the outlines of the new United Nations, discussed the fate of occupied Germany, and negotiated Soviet entry into the war against Japan. They also made vague commitments about free elections in Eastern Europe that each side would interpret very differently. Photographs from Yalta show three allied leaders in apparent harmony. Within two years, their successors were engaged in a global confrontation that would last more than forty years.
How did this happen so quickly? And who was responsible? These questions have generated one of the most extensive historiographical debates in modern history — a debate that has evolved through three major phases, each shaped by the political context of the scholars writing and the archival sources available to them.
The debate matters not just as a historical puzzle. Understanding how the Cold War began illuminates what kind of conflict it was — and whether it had to be fought in the way it was. If it was caused primarily by Soviet aggression, then Western policy of resistance and containment was justified. If it was caused by American expansionism and the failure to understand Soviet security concerns, then a different American foreign policy might have produced a different outcome. If it was produced by structural forces — the collapse of the old European order, the power vacuum left by WWII, the incompatibility of two competing universalist ideologies — then human decisions mattered less than circumstances.
The Grand Alliance and its contradictions
The wartime alliance between the United States, the Soviet Union, and Britain was always a marriage of convenience rather than conviction. The three powers were united by a common enemy — Nazi Germany — but by very little else. The United States and Britain were liberal capitalist democracies; the Soviet Union was a communist one-party state. These were not merely different political systems: they were competing universalist ideologies, each claiming to represent the right way for all humanity to be organised. Their temporary alliance against Hitler did nothing to resolve this fundamental incompatibility.
The alliance's contradictions were visible even during the war. The Soviet Union was consumed by the Eastern Front — by 1945, approximately 27 million Soviet citizens had died, roughly one in seven of the entire population. Stalin's primary postwar goal was to ensure this could never happen again, which meant securing a buffer zone of friendly states in Eastern Europe and extracting reparations from Germany to rebuild the Soviet economy. The United States, by contrast, emerged from the war with its homeland undamaged and its economy producing half the world's industrial output. Its primary goals were the creation of an open international economic order (free trade, stable currency, access to markets) and the prevention of Soviet domination of Europe.
Yalta to Potsdam: the alliance fractures
At Yalta in February 1945, the three leaders reached agreements that were simultaneously genuine compromises and deferred conflicts. On Germany: it would be divided into zones of occupation and forced to pay reparations (the exact amount was left unspecified). On Eastern Europe: Stalin agreed to "free and unfettered elections" in Poland and other countries liberated by the Soviet army — but Soviet and Western interpretations of what this meant were very different. Stalin understood "friendly governments" to be a minimum security requirement; Roosevelt and Churchill understood "free elections" to mean what the words said.
By Potsdam in July 1945, the tone had changed sharply. Roosevelt had died; his successor Harry Truman was less committed to Soviet-American cooperation and was briefed, on the first day of the conference, that the United States had successfully tested an atomic bomb. Truman mentioned this to Stalin obliquely; Stalin appeared unimpressed but was in fact deeply alarmed. The Soviet atomic bomb programme was immediately accelerated.
The critical year: 1946–1947
The Cold War's emergence as a recognisable strategic confrontation can be dated with some precision to the period between March 1946 and March 1947. In March 1946, Churchill gave his "iron curtain" speech in Fulton, Missouri, publicly describing Soviet policy in Eastern Europe as the creation of an authoritarian bloc. In February 1946, Stalin had given a speech implying that war between capitalism and communism was inevitable. In February 1946, George Kennan — a senior American diplomat in Moscow — sent the Long Telegram, an 8,000-word analysis of Soviet motivations that became the intellectual foundation of containment. And in March 1947, Truman addressed Congress to request aid for Greece and Turkey — the speech that launched the Truman Doctrine and formalised the Cold War as official American policy.
Assessing the schools of thought
Each of the three interpretive schools captures something real about the origins of the Cold War — and each has significant weaknesses. A sophisticated historical argument does not simply pick one school and dismiss the others: it shows how and why each captures a partial truth, and constructs a synthesis that is more adequate to the evidence than any single approach.
Does the question of blame matter?
The debate about Cold War origins is not merely an academic exercise in historical attribution. It has real political stakes — both historical and contemporary. If the Cold War was caused primarily by Soviet aggression, then Western policy of firm resistance and military deterrence was correct — and the eventual collapse of the Soviet Union can be read as vindication. If it was caused primarily by American expansionism and failure to take Soviet security concerns seriously, then the lesson is that great power rivalry can produce catastrophic consequences even when neither side has genuinely aggressive intentions — a lesson with obvious contemporary relevance.
The debate also illuminates something fundamental about how historical knowledge is produced: the school that dominated in any given period was shaped as much by the political context in which historians were writing as by the evidence available. Orthodox interpretations dominated when the US was fighting the Cold War; revisionism flourished during Vietnam and Watergate, when American foreign policy credibility was at its lowest; post-revisionism emerged as archives opened. This is not relativism — the evidence genuinely matters, and post-1991 Soviet archives have settled some questions decisively. But it is a reminder that historians are always writing from somewhere.
The Cold War as a structural conflict
Perhaps the most important insight of the post-revisionist synthesis is that the Cold War was not simply the product of specific decisions by specific individuals — though those decisions mattered. It was also produced by structural conditions: the collapse of the old European order in WWII, the power vacuum that result created, and the presence of two competing universalist ideologies — liberal capitalism and Soviet communism — each of which claimed to represent the right way for the entire world to be organised. These structural conditions meant that even well-intentioned decisions by both sides had a tendency to look like aggression to the other. Understanding this dynamic is essential to understanding not just the origins but the whole course of the Cold War — including its eventual end, which you will examine in Package C (Cold War Aftermath).