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The Cold War did not begin with a single declaration or a single shot but emerged, over roughly two years, from the disintegration of the wartime Grand Alliance between the United States, the Soviet Union and Britain. An alliance forged solely to destroy Nazi Germany had no shared vision for the peace that followed; the moment the common enemy was gone, the partners' incompatible aims, ideologies and security fears reasserted themselves. By 1947 the wartime language of cooperation had been replaced by the language of two hostile camps, and the framework of confrontation that would last over four decades was substantially in place.
The central question for the A-Level historian is one of causation and responsibility: who or what was primarily to blame for the breakdown — Soviet expansionism, American assertiveness, or the structural incompatibility of two rival systems thrown into the power vacuum left by Germany's defeat? This is not a question with a single textbook answer, and the examination rewards candidates who can weigh the competing explanations and the contemporary evidence rather than recite a verdict. This lesson builds the narrative and analysis of 1945–1947 and then trains the AO2 source-evaluation skill — the close reading of telegrams, speeches and diplomatic cables — that the Paper 2 examination places at its centre.
Key Question: Was the breakdown of the Grand Alliance between 1945 and 1947 caused primarily by Soviet expansionism, by American provocation, or by the structural incompatibility of two rival systems competing for the vacuum left by Germany's defeat?
Key Definition: The Cold War describes the period of geopolitical tension between the United States and the Soviet Union (and their respective allies) from approximately 1945 to 1991, characterised by ideological rivalry, a nuclear arms race, proxy wars and propaganda — but no direct, declared military confrontation between the two superpowers themselves.
This lesson opens Component 2R, The Cold War, c1945–1991, a Paper 2 DEPTH study. Depth study means the examination rewards close, granular, source-led analysis of a relatively short span rather than the long sweep of a breadth paper. The origins of the Cold War sit at the very start of Part One ('The Origins of the Cold War, c1945–1955') and are the indispensable point of departure: every later episode — Berlin, Korea, the missile crisis, détente, the collapse of 1989–91 — is shaped by how and why the wartime alliance fractured.
The Assessment Objectives are weighted as follows. AO1 (knowledge and understanding deployed to analyse and reach substantiated judgements) carries the largest share across the paper and dominates the Section B essays. AO2 — the analysis and evaluation of primary sources and contemporary opinion in their historical context — is the headline skill of Paper 2 Section A, where you are given source extracts and asked to assess their value to a historian. AO3 (the analysis and evaluation of historians' differing interpretations) is examined directly in other components but is a transferable analytical habit, and engaging with the rich Cold War historiography sharpens the judgement that Section B demands. Throughout, frame your analysis using the second-order concepts: causation (long- versus short-term, and the relative weight of ideology, security and personality), change and continuity, and the significance of individual events.
Concretely, Paper 2 is structured as Section A (a single compulsory primary-source question carrying 30 marks, targeting AO2) and Section B (a choice of essay questions carrying 25 marks each, predominantly AO1 with sustained analytical judgement). A depth study such as 2R is examined on the detail — precise dates, conferences, doctrines, statistics and individuals — deployed to sustain argument, not narrated for its own sake. For this opening topic that means commanding the chronology of the conferences and the Eastern European takeovers, and the contemporary sources (the Long and Novikov Telegrams, the Iron Curtain speech) through which the breakdown can be reconstructed and evaluated.
The Grand Alliance of 1941–1945 was always a marriage of convenience. The USSR, USA and Britain were united only by their common enemy, Nazi Germany; beneath the surface, deep ideological hostility persisted from the moment of its formation. The West had intervened against the Bolsheviks in the Russian Civil War (1918–21); Stalin in turn had signed the Nazi-Soviet Pact with Hitler in August 1939, partitioning Poland with Germany. Each side entered the war remembering the other's earlier hostility. Stalin further suspected — with some justification in his own mind — that the Western powers had deliberately delayed the Second Front (the cross-Channel invasion, finally launched on D-Day, 6 June 1944) so that the USSR would bleed the Wehrmacht white; the Soviet Union ultimately suffered some 27 million dead, a figure that shaped Stalin's absolute determination never again to be invaded through Eastern Europe.
| Factor | Detail | Significance |
|---|---|---|
| Ideological incompatibility | Capitalism versus communism; liberal democracy versus the one-party state and command economy | Fundamental values were irreconcilable; each side saw the other's system as a threat to its own survival |
| Mutual suspicion | Western intervention in the Russian Civil War; the Nazi-Soviet Pact of 1939; the perceived delay of the Second Front | Deep, long-standing distrust predating the war and surviving it |
| Competing war aims | The USA wanted open markets, self-determination and a liberal world order; the USSR wanted territorial security and a buffer of friendly states | Two incompatible visions of the post-war settlement |
| Power vacuum | The destruction of German and Japanese power left a vacuum at the heart of Europe and in Asia | Both superpowers moved to fill it, and their advancing armies met in the middle of a prostrate continent |
The structural point is decisive for analysis: the alliance had been negative — defined by what it opposed — and possessed no positive shared programme. Once Germany was beaten, there was nothing left to hold it together, and a great deal, accumulated over a quarter-century, to drive it apart.
Roosevelt, Churchill and Stalin met in the Crimea with the war in Europe nearing its end and the Red Army already deep inside Poland. The conference was conducted in a still-cooperative spirit, but its agreements contained the ambiguities that would poison the peace.
The ambiguity of the phrase 'free elections' became a source of bitter dispute. Stalin read it as permitting governments friendly to Moscow — which, given the strength of anti-Soviet feeling in Poland, meant communist-dominated ones; the West expected genuine multi-party democracy. Both could plausibly claim the other had broken the spirit of Yalta, and both did.
By Potsdam the political landscape had shifted dramatically. Roosevelt had died on 12 April 1945 and been replaced by the blunter, more suspicious Harry Truman, who as Vice-President had been kept largely ignorant of high diplomacy. Churchill was replaced mid-conference by Clement Attlee after Labour's general-election victory. Most importantly, Truman arrived knowing the atomic bomb had been successfully detonated in the Trinity test of 16 July 1945 — and during the conference, on 6 and 9 August, atomic weapons were used against Hiroshima and Nagasaki, transforming the strategic balance.
| Issue | Outcome |
|---|---|
| Germany | Division into zones confirmed; each occupying power to extract reparations primarily from its own zone, with the USSR also drawing from the West in exchange for food |
| Poland | The western border was effectively set at the Oder-Neisse line; the Soviet-backed government's dominance was a fait accompli the West could not reverse |
| Atomic bomb | Truman informed Stalin obliquely of a 'powerful new weapon'; Stalin, already aware through espionage, feigned indifference and urged its use |
| Reparations | Sharp disagreement over amounts; the zonal compromise left both sides dissatisfied and foreshadowed the economic division of Germany |
Exam Tip: Contrast the atmosphere of the two conferences. Yalta, for all its ambiguities, was a meeting of partners; Potsdam was a meeting of rivals. The change of personnel (Truman for Roosevelt) and, above all, the atomic monopoly altered the psychological balance — though historians disagree fiercely about whether the bomb was used to intimidate the USSR or simply to end the Pacific war.
Between 1945 and 1948 the Soviet Union systematically established communist regimes across the territory its armies had liberated. The process — later dubbed by the Hungarian communist Mátyás Rákosi the 'salami tactics' — followed a recognisable pattern: broad coalition governments including communists were formed, then non-communist opponents were sliced away one at a time through intimidation, control of the key ministries (especially the interior ministry and thus the police), rigged elections and, where necessary, force.
| Country | Communist control consolidated | Method |
|---|---|---|
| Bulgaria | 1946 | Opposition leader Petkov tried and executed; sham elections |
| Poland | 1947 | Rigged elections of January 1947; suppression of Mikołajczyk's Peasant Party |
| Romania | 1947 | King Michael forced to abdicate; opposition parties banned |
| Hungary | 1947–48 | 'Salami tactics'; the Smallholders' majority dismantled piecemeal |
| Czechoslovakia | 1948 | The Prague coup of February 1948 — a communist seizure of power that shocked Western opinion |
Two qualifications matter for balanced analysis. First, Soviet behaviour was not uniform: in Finland the USSR tolerated a non-communist democracy in exchange for neutrality, and in Czechoslovakia a freely-elected coalition functioned until 1948, suggesting Stalin's priority was a secure sphere rather than ideological uniformity for its own sake. Second, from Moscow's vantage point this was defensive — the construction of the buffer zone that the catastrophe of 1941 seemed to demand. The historian Hugh Seton-Watson described the imposition of communism as a 'revolution from above', driven by Soviet power rather than rising from genuine popular support; whether one reads it as aggression or as security is the crux of the origins debate.
The Western reaction to this consolidation matters for assessing responsibility, because perception drove policy as much as fact. To Washington and London, the methods used in Poland and Romania — the rigged ballots, the captive interior ministries, the show trials — looked like the systematic export of a totalitarian model and a flagrant breach of the Yalta Declaration on Liberated Europe. To Stalin, by contrast, a Western insistence on genuinely 'free' elections in countries with strong anti-Soviet traditions was tantamount to demanding hostile governments on the very invasion route along which Germany had twice come. The same set of events thus carried opposite meanings on either side of the emerging divide, and each side's response — Western protest and the turn towards containment, Soviet tightening of the grip — confirmed the other's worst fears. This is why the breakdown is best analysed not as the unfolding of one side's pre-formed plan but as an interactive spiral in which defensive measures were read as aggression and answered in kind.
A disciplined answer separates the types of cause at work and weighs their relative force rather than listing grievances. Three strands intertwine. Ideology supplied the deep, long-term incompatibility: a Marxist-Leninist state committed in principle to the eventual triumph of world socialism faced a liberal-capitalist power committed to an open, market-based international order, and each genuinely regarded the other's system as a mortal threat to its own. Security supplied the immediate motive force: the Soviet determination to control Eastern Europe flowed from the trauma of 1941 and the loss of some 27 million lives, while the American drive to rebuild and bind Western Europe flowed from the lesson of the 1930s that power vacuums invited aggression. Personality and contingency supplied the catalysts: the death of Roosevelt and the arrival of the blunter Truman, the suspicious and ruthless character of Stalin, and the shock of the atomic bomb all sharpened a confrontation that structures alone made likely but did not wholly determine.
| Type of cause | Driving factor | Effect on the breakdown |
|---|---|---|
| Long-term / structural | Ideological incompatibility of capitalism and communism | Made some rivalry almost inevitable once the common enemy was gone |
| Underlying / security | Mutual fear in the power vacuum left by Germany's defeat | Turned rivalry into an active competition for control of Europe |
| Short-term / contingent | Truman's accession, Stalin's character, the atomic monopoly | Hardened and accelerated the rupture; closed off compromise |
The strongest judgement holds these together: structural incompatibility created the conditions for conflict, the security dilemma supplied the mechanism by which each side's defensive moves alarmed the other, and contingent factors of personality and timing determined the speed and bitterness with which the alliance collapsed. To privilege any one strand alone — 'it was all ideology', 'it was all Soviet aggression', 'it was all the bomb' — is to mistake a single thread for the whole rope.
The breakdown was registered in a series of landmark texts that are themselves the prime AO2 sources for this topic.
In February 1946 the American diplomat George Kennan sent his 'Long Telegram' from the Moscow embassy, arguing that Soviet hostility was rooted in ideology and the regime's internal needs and could not be charmed away, only contained. On 5 March 1946, at Westminster College in Fulton, Missouri, Winston Churchill — now out of office but speaking with Truman beside him — delivered the Iron Curtain speech, declaring that 'from Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent'. Stalin responded furiously in Pravda, comparing Churchill to Hitler and accusing the West of seeking to encircle the USSR. In September 1946 the Soviet ambassador Nikolai Novikov sent the mirror-image 'Novikov Telegram', portraying the United States as bent on world domination through its economic and military supremacy. Read side by side, the Long and Novikov Telegrams capture the security dilemma at the heart of the Cold War: each power, taking defensive measures against the other, appeared to the other as an aggressor.
timeline
title The Breakdown of the Grand Alliance 1945–1947
Feb 1945 : Yalta Conference : 'Free elections' promised
Apr 1945 : Roosevelt dies : Truman becomes President
Jul-Aug 1945 : Potsdam : Atomic bomb tested then used
Feb 1946 : Kennan's Long Telegram : Intellectual roots of containment
Mar 1946 : Churchill's Iron Curtain speech (Fulton)
Sep 1946 : Novikov Telegram : The Soviet mirror-image
1947 : Communist consolidation across Eastern Europe
Paper 2 Section A presents primary sources and asks you to evaluate their value to a historian investigating a given enquiry. The disciplined method is to weigh four dimensions — provenance (who, when, where), tone and emphasis, purpose (why produced, for whom), and content set against your own contextual knowledge — and to reach an overall judgement about utility that holds limitations and strengths together. Crucially, a source's bias or ideological distortion is not a reason to dismiss it; a slanted source is often most valuable as evidence of the attitudes, fears or propaganda aims of its author — and in the Cold War, where rival ideologies framed every document, this is the single most important AO2 habit.
Worked exemplar — a representative source type: George Kennan's 'Long Telegram', Moscow, February 1946. A characteristic and superbly attested source for this topic is the cable Kennan, then chargé d'affaires at the US embassy in Moscow, sent to the State Department, arguing (in substance, as the standard accounts record) that the Soviet leadership's hostility flowed from ideology and the internal insecurity of the regime, that it respected only force, and that it could be contained by firm, patient, long-term counter-pressure. (Treat this as a representative type — characterise it by its provenance; do not rely on an invented verbatim quotation.)
Apply the same grid to any source the examiner sets: the Novikov Telegram (purpose = warn Moscow of US ambitions; value = candid evidence of Soviet threat-perception), Churchill's Iron Curtain speech (provenance = a public address by an out-of-office statesman; value = it shaped and crystallised Western opinion, even as its rhetoric exceeded his formal authority), or a Yalta or Potsdam communiqué (value = the agreed text whose very ambiguity caused the later dispute).
Few topics in modern history have generated as fierce or as well-defined a historiographical debate as the origins of the Cold War, and the schools map directly onto the question of responsibility.
The orthodox (traditional) interpretation, dominant in the West in the 1940s and 1950s, placed responsibility squarely on the Soviet Union: Stalin was an ideologically-driven expansionist whose subjugation of Eastern Europe forced a reluctant America to respond. Herbert Feis and Arthur Schlesinger Jr. are representative; the latter argued that the deeper cause was the messianic, universalist nature of Soviet communism, which could not coexist with a pluralist world.
The revisionist school, emerging in the 1960s amid disillusion with the Vietnam War, reversed the charge. William Appleman Williams (The Tragedy of American Diplomacy, 1959) argued that the driving force was American economic expansionism — the 'Open Door' demand for global markets — which made Soviet-style autarky and a closed Eastern bloc intolerable to Washington. Gabriel Kolko (The Limits of Power, 1972) likewise saw US policy as the aggressive defence of a capitalist world order, and Gar Alperovitz (Atomic Diplomacy, 1965) controversially argued that the bombs dropped on Japan were aimed as much at intimidating the USSR as at ending the Pacific war.
The post-revisionist synthesis, which became dominant from the 1970s and especially after the Cold War ended, holds that both sides contributed and that structural factors — the power vacuum, mutual misperception, the security dilemma — made conflict highly likely whoever sat in the Kremlin or the White House. John Lewis Gaddis is the leading figure; in We Now Know (1997), written after the Soviet archives opened, he restored a degree of Soviet responsibility, arguing that Stalin's character and the nature of his regime made accommodation impossible — but without returning to crude orthodoxy. Melvyn Leffler (A Preponderance of Power, 1992) stresses how American policymakers, pursuing security through overwhelming strength, helped harden the division. The Norwegian historian Odd Arne Westad (The Global Cold War, 2005) and the Russian historian Vladislav Zubok (A Failed Empire, 2007), drawing on newly available evidence, frame the conflict as a clash of two universalist ideologies and emphasise Soviet insecurity as much as ambition.
Exam Tip: The strongest answers avoid simplistic blame and use the historiography to structure a judgement. The post-revisionist synthesis — acknowledging both Soviet and American contributions within a framework of structural incompatibility, while weighing Stalin's particular responsibility in the light of the opened archives — is the most sophisticated and examiner-rewarding position, provided it is argued rather than merely asserted.
Section A — Primary-source question (30 marks; AO2).
'With reference to these sources and your understanding of the historical context, assess the value of these three sources to a historian studying the breakdown of the wartime alliance in the years 1945 to 1947.'
Source A — George Kennan's 'Long Telegram', sent from the US embassy in Moscow, February 1946 (a confidential diplomatic analysis arguing that Soviet hostility is ideological and must be contained). Source B — the Novikov Telegram, sent by the Soviet ambassador in Washington, September 1946 (a confidential analysis arguing that the United States is pursuing global domination). Source C — Churchill's 'Iron Curtain' speech at Fulton, March 1946 (a public address by a former Prime Minister warning the West of Soviet expansion).
The mark scheme rewards evaluation of each source's value through provenance, tone, purpose and content-in-context, reaching a supported overall judgement — not paraphrase.
Mid-band response: 'Source A is useful because Kennan worked at the embassy in Moscow, so he knew about the Soviet Union. He says it is expansionist, which is true because Stalin took over Eastern Europe. Source B is a Soviet source so it is biased and just propaganda against America, which makes it less useful. Source C is by Churchill, who was an important leader, so it is reliable, but he was not Prime Minister any more so maybe it does not count as much. Overall Source A is the most useful.' (Comments on each source and makes a provenance point, but treats Source B as worthless because it is "biased" and offers no overall weighing of value.)
Stronger response: 'Source A is valuable precisely because it is a confidential cable — Kennan was writing to inform his own government, not to persuade the public, so it candidly conveys the American diplomatic establishment's growing conviction that cooperation was impossible. Source B is its mirror image and is useful for exactly the same reason: as a secret Soviet analysis it reveals what Moscow genuinely feared, namely American economic and military supremacy, and shows that each side saw the other as the aggressor. Source C, though a public speech by a man out of office, is valuable because Churchill spoke with Truman beside him and crystallised Western opinion, even if its dramatic rhetoric went beyond his formal authority.' (Genuine value-in-context for each, purpose handled well, the mirror-image point grasped; judgement implied rather than fully sustained across the set.)
Top-band response: 'Taken together the three sources are valuable for different layers of the breakdown, and their limitations are as instructive as their content. Sources A and B are most useful read as a pair, because between them they document the security dilemma itself: each is a confidential analysis, and so candid, yet each reads the other side's defensive consolidation as a drive for domination — A telling us how Washington came to see containment as necessary, B telling us that Moscow simultaneously felt encircled by American power. Their very symmetry is the historian's prize, since it shows the conflict arising less from one side's aggression than from mutual misperception. Source C supplies what the cables cannot: the moment private diplomatic alarm became public, mobilising Western opinion behind confrontation — though, as the words of a statesman without office, it must be weighed as advocacy that ran ahead of official policy, which is why Truman could publicly distance himself from it. A historian would therefore privilege no single source but triangulate them — American perception (A), Soviet perception (B) and the public crystallisation of the rupture (C) — concluding that the alliance broke down because each superpower, acting defensively, appeared to the other as a threat, and that this mutual fear was then hardened into doctrine and rhetoric.' (Sustained judgement; value AND limitation weighed in context for every source; the symmetry of A and B turned into analytical leverage.)
Examiner-style commentary: The discriminator between the bands is the handling of the two confidential telegrams. The Mid-band answer dismisses the Soviet source as 'biased propaganda'; the Stronger answer rescues it as evidence of genuine Soviet fear and grasps the mirror-image; the Top-band answer makes the symmetry of A and B do the analytical work, building the security-dilemma reading and placing the public speech (C) as the moment private alarm went public. Note that no fabricated quotations are needed — the sources are characterised by type and provenance.
The Cold War emerged between 1945 and 1947 from the collapse of an alliance that had never been more than a marriage of convenience. With Nazi Germany destroyed, the incompatible aims, ideologies and security fears of the United States and the Soviet Union reasserted themselves across the power vacuum of a ruined Europe. Ambiguous wartime agreements at Yalta and Potsdam, the consolidation of Soviet control over Eastern Europe, and the hardening of mutual perception — registered in the Long and Novikov Telegrams and Churchill's Iron Curtain speech — converted wartime partners into rivals. Whether the breakdown was primarily Soviet expansion, American assertiveness or the structural logic of a bipolar world remains the central interpretive question. The analytical task — and the examination reward — lies in weighing those explanations and in evaluating the contemporary sources through which the rupture can be reconstructed.
This content is aligned with the AQA A-Level History (7042) specification.