By late 1943 the course of World War II had decisively shifted. After the Soviet victory at Stalingrad (Feb. 1943) and the crushing of German forces at Kursk (July 1943), the Axis powers were retreating on all fronts. In Italy the Allies had invaded Sicily and toppled Mussolini, and in the Pacific the U.S. was advancing from Guadalcanal to Bougainville.  With the pendulum swinging to Allied advantage, the “Big Three” (Churchill, Roosevelt, StalinStalin Joseph Vissarionovich Stalin (18 December 1878 – 5 March 1953) was a Soviet politician, dictator and revolutionary who led the Soviet Union from 1924 until his death in 1953. Read More) recognized the need to plan not only final offensives but also the postwar settlement.  As one commentator noted, against “a decisive turn of the tide in the Allies’ favour, the ‘Big Three’ convened in Tehran to draw up the road-map for the drive to ultimate victory.” .  This preparation ranged from battlefield strategy (opening a “second front” in Europe) to sketching a new world order. Prior meetings between Churchill and Stalin and Churchill and Roosevelt were superseded by the first three-way discussions.

The Moscow Conference (October 1943): Four Powers in Alliance

In October 1943 the U.S., U.K. and USSR met in Moscow to coordinate strategy.  The principal participants were U.S. Secretary of State Cordell Hull, British Foreign Secretary Anthony Eden, and Soviet Foreign Minister Vyacheslav Molotov.  Significantly, the Chinese Ambassador to Moscow, Foo Bingchang, was invited to join as a fourth partner.  The four negotiated through late October and issued a Four-Power Declaration on General Security.  This Moscow Declaration contained seven clauses affirming continued allied cooperation in war and peace.  Most strikingly, its fourth clause declared that the Allies “recognize the necessity of establishing at the earliest practicable date a general international organization” based on the sovereign equality of all states – “large and small” – to maintain peace .  In other words, the idea of a United Nations for postwar security was explicitly endorsed.  This was the first formal articulation by the great powers of a global peacekeepingPeacekeeping Full Description:A mechanism not originally explicitly defined in the Charter, involving the deployment of international military and civilian personnel to conflict zones. Known as the “Blue Helmets,” they monitor ceasefires and create buffer zones to allow for diplomatic negotiations. Peacekeeping was an improvisation developed to manage Cold War conflicts that the Great Powers could not agree to solve forcibly. It operates on the principles of consent (the host country must agree), impartiality, and the non-use of force except in self-defense. Critical Perspective:While often celebrated, peacekeeping is often criticized for “freezing” conflicts rather than solving them. By stabilizing the status quo, it can inadvertently remove the pressure for political solutions, leading to “forever wars” where the UN presence becomes a permanent feature of the landscape. Furthermore, peacekeepers have faced severe criticism for failures to protect civilians and for sexual exploitation and abuse in host communities.
Read more body , and it anticipated later work at Dumbarton Oaks (1944) and San Francisco (1945).

The inclusion of China sent a powerful signal: the Allies raised China’s status to that of a full Allied power, foreshadowing its permanent UN Security CouncilSecurity Council Full Description:The Security Council is the only UN body with the authority to issue binding resolutions and authorize military force. While the General Assembly includes all nations, real power is concentrated here. The council is dominated by the “Permanent Five” (P5), reflecting the military victors of the last major global conflict rather than current geopolitical realities or democratic representation. Critical Perspective:Critics argue the Security Council renders the UN undemocratic by design. It creates a two-tiered system of sovereignty: the Permanent Five are effectively above the law, able to shield themselves and their allies from scrutiny, while the rest of the world is subject to the Council’s enforcement. seat.  The Declaration’s text reflects this: it begins “The Governments of the United States of America, the United Kingdom, the Soviet Union and China, united in their determination…”. 

It vowed continued allied action in the war, joint action on Axis surrender terms, and joint military occupation if needed.  Annexes to the Declaration went further. For example, the three Western powers agreed to establish a European Advisory Commission (EAC) composed of the U.S., U.K. and USSR to plan postwar Europe .  The EAC’s first tasks would include studying how to disarm and “dismember” Nazi Germany, handing it unconditional surrender, and setting terms for other Axis enemies .  In short, Moscow produced both a high-minded vision of a new world organization and concrete machinery (the EAC, an Italian Advisory Council, etc.) for postwar governance.  The dual emphasis on ideals (a general international organization) and power politics (occupation plans, commissions) would characterize Allied planning in 1943–45.

The Big ThreeThe Big Three Full Description:The term used to describe the leaders of the major Allied powers: the United States, the Soviet Union, and the United Kingdom. The United Nations was not a creation of the global community, but largely a negotiated settlement between these three distinct imperial interests. The Big Three refers to the wartime alliance that designed the post-war architecture. Through a series of conferences (Tehran, Yalta, Potsdam), these powers haggled over the shape of the UN. The structure of the organization reflects the compromises made between American liberal capitalism, Soviet communism, and British imperialism. Critical Perspective:This term highlights the oligarchical origins of the UN. While the organization claims to represent “We the Peoples,” its DNA was encoded by three men representing the military victors. The concerns of the rest of the world—particularly the colonized nations and the smaller European states—were largely marginalized or ignored during the foundational drafting phase.
Read more’s Motivations

Each Allied leader came with distinct goals.  Franklin D. Roosevelt was bent on forging a durable peace through great-power cooperation.  He championed a vision of postwar order in which the major Allies (the U.S., USSR, U.K., and China) would act as “policemen” of the world.  Roosevelt had already conceived this “Four Policemen” concept by May 1942, and at Tehran he outlined it to Stalin .  Under this plan, a future United Nations would be dominated by these four powers, who would have “the power to deal immediately with any threat to the peace” .  In practice, Roosevelt wanted guarantees of collective security (to safeguard smaller nations and U.S. interests) while giving each great power a leading role.  He also strongly advocated China’s inclusion (as the fourth policeman) to limit Soviet and British monopoly and to bolster Asian support.

Winston Churchill was primarily focused on Europe and the empire.  He supported operation plans that would liberate Nazi-occupied territories in 1944 (especially launching Overlord in France) but was deeply concerned about Soviet influence in Eastern Europe.  At Tehran he pressed Stalin on the Polish question.  Stalin insisted on moving Poland’s border westward to the Curzon line (shifting Poland into former German territory) and reabsorbing the Baltic states.  Churchill (with Roosevelt) eventually agreed to shift Poland’s western border to the Oder–Neisse line, compensating Poland with German lands, and extract Soviet assurances that the Baltic republics would only join the USSR “after a free vote” .  This compromise – approving Stalin’s territorial gains while insisting on nominal plebiscites – highlighted Churchill’s uneasy balancing of Soviet demands and Allied principles.  In the Middle East, Churchill was also navigating local politics (e.g. guaranteeing Iran’s sovereignty after the war ) and protecting postwar access to the Mediterranean and oil routes.

Joseph StalinStalin Joseph Vissarionovich Stalin (18 December 1878 – 5 March 1953) was a Soviet politician, dictator and revolutionary who led the Soviet Union from 1924 until his death in 1953. Read More approached the conferences with strict realpolitik.  His overriding goal was Soviet security.  Years of warfare had taught Stalin to prioritize buffer zones and friendly governments on the USSR’s borders.  As historian Geoffrey Roberts notes, the Soviet leadership sought “security of the socialist system” by creating “a sphere of influence in Eastern and Central Europe – a zone of Soviet strategic and political predominance” .  In practice this meant shifting Poland’s frontier east (annexing territories), controlling the Balkans, and gaining military bases (e.g. in Iran and the Pacific).  At Moscow, Stalin calculated cautiously: he agreed to endorse a new world organization, but only if it rested on “the enforcement power of the Big Three” and essentially left each to his own zones of responsibility .  Litvinov (USSR) even argued that no global peace-keeping body could function without a division of the world among the great powers .  In effect, Stalin wanted a tripartite balance of power: the Big Three acting as guarantors, rather than an open multilateral system.  He was willing to negotiate postwar plans (e.g. shelving Poland until the postwar commissions) but stood firm on Soviet aims.  Winston Churchill privately described Stalin’s approach as “unabashed Realpolitik” , a sentiment borne out by the annexes Stalin demanded at Eden’s 1941 Moscow meeting and later conferences.

In sum, each leader mixed ideals with self-interest.  Roosevelt brought idealistic language (four freedoms, human rights) and aimed to lock in U.S. global leadership in a liberal order.  Churchill defended Britain’s strategic interests in Europe and Asia.  Stalin pursued a pragmatic pursuit of security, always wary of diluting Soviet gains in a broad international bureaucracy.  As Melvyn Leffler emphasizes, the wartime alliance was fundamentally shaped by power politics: even as they spoke of common goals, each side maneuvered to maximize its postwar influence.  The Moscow and Tehran talks reflected this uneasy unity – the Allies publicly agreed on lofty principles, but privately reserved space to protect their own interests.

Key Agreements of the Tehran Conference (Nov.–Dec. 1943)

Figure: Stalin, Roosevelt, and Churchill during the Tehran Conference (Nov. 28–Dec. 1, 1943) .

In late November 1943 the Tehran Conference brought together Roosevelt, Churchill, and Stalin in person (the first time the three heads of government met together) .  This summit combined detailed military planning with the first face-to-face discussion of postwar international institutions.  On strategy, the leaders made decisive commitments.  The Americans and British finally agreed to launch Operation Overlord – the Normandy invasion – by May 1944, responding to Stalin’s long-standing demand for a Western front .  In turn, Stalin pledged to stage a major new Soviet offensive on the Eastern Front at the same time, to divide German forces .  The Big Three also discussed the war in Asia: Stalin agreed (in principle) that the Red Army would enter the war against Japan once Germany was defeated, in exchange for Soviet control of the Kuril Islands and southern Sakhalin (to be confirmed at Yalta) .

On political and territorial issues, Tehran set several important markers.  The fate of Poland was reopened: Stalin reiterated his demand for Poland’s eastern border to shift to the old Curzon line, effectively incorporating eastern Poland into the USSR.  The Allied leaders conceded this in principle and agreed to place Poland’s western border on the Oder–Neisse rivers, giving Poland lands taken from Germany .  Stalin also secured Roosevelt’s promise to respect a Soviet-style referendum in the Baltic states, rather than any external supervision .  The three powers also issued a separate declaration on Iran, pledging to respect Iran’s independence and territorial integrity after expelling Axis influence .

Perhaps most significant for world order, Tehran saw Roosevelt and Stalin privately revive discussions about a global peacekeeping body.  Building on the Moscow Declaration, Roosevelt sketched for Stalin the Four-Policemen concept of the United Nations .  As State Department historians recount, Roosevelt “outlined his vision” of a future UN dominated by four great powers (the U.S., U.K., USSR, and China) who would act as guarantors of peace .  This was not a fully fleshed-out structure, but a powerful idea: under Roosevelt’s plan, smaller Allied nations would be members of the general UN, while the “policemen” could take emergency action.  (This notion would inform the later UN Security Council’s composition.)

Key outcomes of the Tehran Conference included:

Operation Overlord agreed: Allies commit to a cross-Channel invasion by spring 1944, with Soviet attacks timed to distract German forces . Soviet entry into war on Japan: Stalin promises to declare war on Japan after Germany’s defeat, in exchange for territorial concessions (as later formalized at Yalta). Postwar Europe discussed: Polish and German frontiers are sketched (Poland shifted west to Oder-Neisse) ; a European Advisory Commission is to study German occupation zones and border issues. “Four Policemen” UN concept: Roosevelt and Stalin talk privately about a postwar world organization in which the major Allies would have special enforcement authority . Iran Declaration: The Allies reaffirm Iran’s sovereignty and pledge assistance, an important signal to Middle Eastern Allies .

After Tehran, Roosevelt believed he had “won Stalin’s confidence” by securing Soviet cooperation on Overlord and the UN plan .  Stalin, for his part, had extracted further unofficial recognition of Soviet claims in Europe, to be finalized later.  The communiqué issued at Tehran proclaimed Allied unity and “our determination that our nations shall work together in war and in peace” .  Yet beneath the cooperative language, each side still guarded its prerogatives – a pattern noted by historians like Gaddis and Leffler, who stress that wartime diplomacy was a blend of idealism and self-interest.

The Role of China and Smaller Allies

China’s role at these conferences was largely symbolic but significant.  At Moscow, including China as a full partner signaled the Allies’ intent to make China a postwar great power.  The Chinese Foreign Minister Chiang Kai-shek had participated in related talks (Cairo, Nov. 1943) on Asia strategy, and Ambassador Foo represented China in Moscow .  By sharing the Declaration on General Security, China joined the “Big Four” in calling for a new international organization .  Roosevelt’s Four-Policemen vision likewise included China as a permanent member , reflecting U.S. aims to balance Soviet influence.  In practice, China’s inclusion offered moral support and a stake in the UN, though its armies suffered on the Asian front and could contribute little to European affairs.

Smaller Allied nations were on the margins of these conferences.  At Moscow, issues affecting them were noted but not settled.  The agenda included “Relations between USSR and Poland” and “Future of Poland and the Danubian/Balkan countries,” but the four powers deferred final decisions to commissions .  Similarly, the Moscow agreements established an Italian Advisory Council that, for the first time, included France, and planned to add Greece and Yugoslavia once those countries were liberated .  This showed some recognition of smaller nations’ stakes (Italy’s neighbors and former victims of fascism), but these governments had no seat at the Big-Four table.  In Europe, power lay with the occupying Allies and the tripartite commissions (the EAC in London, and later the Allied Control Council in Germany) rather than with exiled or minor governments.  As a result, leaders like Churchill and de Gaulle later had to negotiate for their interests (e.g. France gained a Council seat only by Yalta) after the Great Powers set the broad terms.  In Asia, Allied consultations at Cairo and Tehran acknowledged Chinese participation, but countries like India, Burma and the Philippines were not represented at the top level (though Roosevelt assured Chinese leader Chiang of U.S. support for postwar national self-determinationSelf-Determination Full Description:Self-Determination became the rallying cry for anti-colonial movements worldwide. While enshrined in the UN Charter, its application was initially fiercely contested. Colonial powers argued it did not apply to their imperial possessions, while independence movements used the UN’s own language to demand the end of empire. Critical Perspective:There is a fundamental tension in the UN’s history regarding this term. While the organization theoretically supported freedom, its most powerful members were often actively fighting brutal wars to suppress self-determination movements in their colonies. The realization of this right was not granted by the UN, but seized by colonized peoples through struggle.).

Historiographical Perspectives

Scholars have long debated the meaning of these wartime conferences.  John Lewis Gaddis, for example, interprets Roosevelt’s diplomacy as a grand strategy of building a liberal order: by Tehran, Roosevelt hoped to bind Stalin into an institutional framework and thereby reduce Soviet unpredictability.  The emphasis on a “general international organization” and the Four-Policemen plan reflect this vision.  In contrast, Geoffrey Roberts and others underscore Stalin’s realism and opportunism.  Roberts points out that Soviet leaders saw the war as an “opportunity to achieve [their] main goal: the security of the socialist system” via friendly regimes in Eastern Europe .  He notes that wartime diplomacy was driven by “calculations of security, power, and diplomacy” for each side .  Melvyn Leffler similarly emphasizes that “power politics” underlay the alliance: even while the Allies professed common aims, each maneuvered to secure postwar dominance. Warren Kimball has written on Roosevelt’s insistence on principles (like human rights and colonial self-determination) that sometimes strained the alliance, a tension evident in Roosevelt’s push for including China and Africa’s future. Elizabeth Borgwardt highlights how American planners infused moral language into these talks (Four Freedoms, rights) – yet acknowledges that such idealism was constrained by real-world negotiations with Churchill and Stalin.

Conclusion: Inching Toward the United Nations

The Moscow and Tehran conferences of 1943 were pivotal precursors to the United Nations.  They did not alone create the UN – the detailed charter would be hammered out at the Dumbarton Oaks Conference in summer 1944 and the United Nations Conference in San Francisco in 1945 – but they laid the groundwork.  In Moscow the Allies formally embraced the idea of an international organization for peace and set up joint commissions to plan Europe.  In Tehran they not only locked in military strategy for victory but began sketching the great-power “police” framework of the UN .  These 1943 summits thus mark the beginning of postwar planning: a mix of principled vision and great-power bargaining.  As one historian observes, the Big Three proclaimed they would “work together in war and in peace,” yet left critical details (borders, occupation zones, voting rules) to be resolved later .  In that sense, Moscow and Tehran did not finalize the United Nations – they hinted at it.  But by building an alliance of the four major Allies and by committing to joint action, they certainly planted the seeds of what would become the UN.  The real architecture of the organization (the Security Council with vetoes, the General Assembly with all states) was constructed in the year that followed, based on the ideas first broached at these conferences.