Origins of the Cold War and Bipolarity
FoundationAfter the Second World War the United States and the Soviet Union turned from wartime allies into rivals: ideological opposition, disputes over postwar settlements and a chain of crises slid the world into the Cold War between 1945 and 1949. The Iron Curtain speech, the Truman Doctrine, the Marshall Plan, the Berlin Blockade and two military alliances created the bipolar world led by Washington and Moscow.
- The alliance broke down over ideological opposition plus wartime mistrust — the delayed second front and the secret atomic bomb
- Key chain: 1946 Iron Curtain speech → 1947 Truman Doctrine and Marshall Plan → 1948–49 Berlin Blockade → 1949 NATO and the Soviet atomic test
- The airlift's success defeated the blockade and led to Germany's formal division in 1949
文體小知識：歷史敘事說明文——按時間次序陳述冷戰由同盟破裂到兩極格局成形的過程，配合多角度的責任分析，是歷史科處理國際關係課題的標準文體。
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1During the Second World War the United States, Britain and the Soviet Union allied against the Axis, yet the basis of cooperation was fragile. The Western Allies delayed opening a second front, leaving the USSR to bear the main German assault for years; the United States also developed and used the atomic bomb without informing Moscow, deepening Stalin's distrust. The Soviet Union, advancing across Eastern Europe, installed pro-Soviet governments in Poland, Romania and elsewhere, alarming the West. One side believed in capitalism and free elections, the other in communism and one-party rule — the ideological gulf widened mutual suspicion.
2In 1946 former British prime minister Churchill, speaking in Fulton, Missouri, declared that 'from Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent' — the phrase became the symbol of Europe's division. In March 1947 President Truman asked Congress to aid Greece and Turkey, pledging that the United States would support free peoples resisting armed minorities or outside pressure: the Truman Doctrine, marking the formal start of America's containment policy.
3That June, Secretary of State Marshall launched the European Recovery Program — the Marshall Plan — offering massive aid to rebuild Europe and prevent economic collapse from feeding communism. The USSR barred Eastern European states from joining and answered with the Molotov Plan, splitting Europe's economy in two. In June 1948, after the Western powers introduced currency reform in their zones, Stalin blockaded all land and water routes to force the Allies out of West Berlin; Britain and America ran the Berlin Airlift for nearly a year, supplying over two million people by air until Stalin lifted the blockade in May 1949.
4The crises pushed both sides into alliance. In April 1949 the United States, Canada and ten Western European nations founded the North Atlantic Treaty Organization pledging collective defence; that year the Soviet Union tested an atomic bomb, ending America's nuclear monopoly. In 1955, after West Germany joined NATO, the USSR and its Eastern European satellites formed the Warsaw Pact. Germany was divided into East and West, Europe split into two military blocs, and the world entered the bipolar order led by Washington and Moscow.
5Historians have long argued over responsibility for the Cold War: orthodox writers blamed Soviet expansionism; revisionists pointed to American economic expansionism and atomic diplomacy; post-revisionists saw both sides as victims of misjudgement and mistrust. Whatever the stance, bipolarity shadowed international conflict for the next four decades, shaping Korea, the Cuban Missile Crisis and many other events.
1Summary 重點摘要
After the Second World War the United States and the Soviet Union turned from wartime allies into rivals: ideological opposition, disputes over postwar settlements and a chain of crises slid the world into the Cold War between 1945 and 1949. The Iron Curtain speech, the Truman Doctrine, the Marshall Plan, the Berlin Blockade and two military alliances created the bipolar world led by Washington and Moscow.
2Vocabulary cards Vocabulary
The post-1945 all-out rivalry between the US and Soviet blocs short of direct war — military, economic, diplomatic and propagandist.
Churchill's 1946 Fulton speech describing the division of Europe behind an 'iron curtain'.
The 1947 pledge to support nations threatened by communism, marking the start of containment.
America's core strategy of preventing further communist expansion.
The 1947 European Recovery Program using American aid to rebuild Western Europe.
The 1948–49 Soviet blockade of West Berlin, answered by the Anglo-American Airlift — the first Cold War crisis.
The 1949 collective-defence alliance of the United States, Canada and ten Western European nations.
The 1955 Soviet-led military alliance of Eastern European states, countering NATO.
The world order divided into two blocs led by the United States and the Soviet Union.
The US–Soviet competition in nuclear and conventional weapons, opened by the Soviet atomic test of 1949.
3Step by step Steps
- Step 1: Why the alliance brokeExample: the Grand Alliance fought side by side, but cracks appeared early — the Anglo-Americans delayed the second front until 1944, leaving the USSR to face the main German force for three years; Washington developed the atomic bomb without telling Moscow and later used it as diplomatic leverage; the Soviet Union installed friendly regimes across Eastern Europe. One side stood for capitalism and parliamentary elections, the other for communism and single-party rule — the gulf in aims and systems made trust impossible.
- Step 2: The Iron Curtain speech — rivalry goes publicExample: in March 1946 Churchill, sharing a platform with President Truman at Fulton, Missouri, described Soviet-dominated Europe as separated from the West by an 'iron curtain'. The speech made Anglo-American suspicion public and is seen as a prelude to the Cold War; Stalin denounced Churchill as a warmonger. Remember two details often tested: the speaker was Churchill, not Truman, and the venue was the United States.
- Step 3: The Truman Doctrine and containmentExample: in February 1947 Britain told Washington it could no longer support the Greek government against communist insurgents. Truman asked Congress for 400 million dollars for Greece and Turkey, declaring that the United States must support free peoples resisting armed minorities or outside pressure. This was containment: not to overthrow the USSR by war, but to block any further expansion while awaiting internal change — the master plan of American strategy for the next four decades.
- Step 4: The Marshall Plan — the economic frontExample: postwar Europe faced shortages and industrial ruin, and communist parties flourished in France and Italy. In June 1947 Secretary of State Marshall proposed the European Recovery Program, providing some thirteen billion dollars to sixteen recipient countries over four years. The USSR denounced it as economic imperialism, barred the East from joining and set up its own rival system. Europe's economy split in two: Western Europe revived on American aid while the East entered the Soviet orbit — the Cold War moved from declarations to economic blocs.
- Step 5: The Berlin Blockade — the first head-on crisisExample: occupied Germany was divided into four zones, and Berlin, deep in the Soviet zone, was likewise quartered. In June 1948 the Western powers introduced a new currency in their zones; Stalin saw this as rebuilding Germany against him and blockaded every land and water route to West Berlin, cutting off two million people. Britain and America ran the Airlift — planes landed round the clock, at the peak one every minute, for eleven months — until Stalin lifted the blockade in May 1949. The airlift's success hardened Western resolve, and that same year Germany formally split into two states.
- Step 6: Two alliances and the bipolar worldExample: in April 1949 the North Atlantic Treaty was signed — an attack on one member counted as an attack on all; that August the USSR tested an atomic bomb, ending America's monopoly and opening the arms race. In 1955, after West Germany joined NATO, the Soviet Union formed the Warsaw Pact with seven Eastern European states. Europe was now split in two, alliances faced each other openly, and world politics, economics and military affairs were fully polarised — the Cold War framework under which every later crisis unfolded.
- Step 7: Who was responsible — views from three anglesExample: three schools debate responsibility. The orthodox school, dominant in the 1950s, blamed Soviet expansionism; the revisionist school, prominent during the Vietnam era, criticised American economic expansionism and atomic diplomacy; the post-revisionist school, using newly opened archives, saw both sides propelled by misjudgement and mistrust. In essays, present all three views, then weigh them with evidence — for instance, the Marshall Plan genuinely revived Western Europe while the USSR genuinely controlled Eastern European elections. Balanced multi-angle argument is exactly what essay markers reward.
4Diagrams Diagrams
5Worked example Example
Data question: five events of US–Soviet relations, 1945–1949: A. Truman Doctrine (1947); B. Soviet atomic test (1949); C. Iron Curtain speech (1946); D. Berlin Blockade (1948–49); E. Marshall Plan (1947). Put them in order and, on the question of whether the USA or the USSR bore greater responsibility for the outbreak of the Cold War, present a multi-angle analysis using the sources and your own knowledge. (14 marks)
- Step 1: Order. Correct sequence: C (1946) → A and E (1947) → D (1948–49) → B (1949). A and E share a year and may be placed together.
- Step 2: Case against the USA. The atomic bomb used without consulting Moscow; the Marshall Plan splitting Europe's economy into blocs; NATO as an armed alliance — revisionists argue American economic expansionism and atomic diplomacy provoked the confrontation.
- Step 3: Case against the USSR. Pro-Soviet regimes across Eastern Europe; the Berlin Blockade attempting to expel the Allies; banning the East from Marshall aid — orthodox writers blame Soviet expansionism.
- Step 4: A multi-angle conclusion. Post-revisionists hold that both sides were driven by misjudgement: the ideological gulf turned ordinary security concerns into perceived hostility. Any position is acceptable if argued with evidence from both sides plus a personal verdict — exactly what essay markers require.
- Answer: Order: C→A/E→D→B. Against the USA: the Truman Doctrine and Marshall Plan divided the world into camps and atomic diplomacy deepened Soviet suspicion, so revisionists hold Washington largely responsible. Against the USSR: pro-Soviet regimes in Eastern Europe, the Berlin Blockade and the ban on Marshall aid lead orthodox writers to blame Moscow. Post-revisionists see both powers driven by misjudgement. A personal stance may adopt either side, but must present evidence from both angles plus a conclusion — meeting the essay requirement of multiple perspectives, a clear position and historical evidence.
6Common mistakes Mistakes
7Quick check Quick check
Q1Who coined the phrase 'iron curtain', and in which year?
Q2What policy did the Truman Doctrine mark the start of?
Q3What was the Marshall Plan's official name and purpose?
Q4How did Britain and America keep West Berlin supplied during the blockade?
Q5In which years were NATO and the Warsaw Pact founded?
8Recap Recap
- The alliance broke down over ideological opposition plus wartime mistrust — the delayed second front and the secret atomic bomb
- Key chain: 1946 Iron Curtain speech → 1947 Truman Doctrine and Marshall Plan → 1948–49 Berlin Blockade → 1949 NATO and the Soviet atomic test
- The airlift's success defeated the blockade and led to Germany's formal division in 1949
- NATO (1949) facing the Warsaw Pact (1955) completed the bipolar order
- Responsibility is debated by orthodox, revisionist and post-revisionist schools — essays must argue from multiple angles