Diplomatic history of World War II

The diplomatic history of World War II includes the major foreign policies and interactions inside the opposing coalitions, the Allies of World War II and the Axis powers, between 1939 and 1945.

High-level diplomacy began as soon as the war started in 1939. British Prime Minister Winston Churchill forged close ties with France and sought close ties with the United States, especially through his relationship with President Franklin Roosevelt. When Russia joined the war in June 1941, the Grand Alliance expanded to a three-way relationship among Churchill, Roosevelt and Joseph Stalin of the Soviet Union. American diplomacy stepped up after it entered the war in December 1941 and was bolstered by large quantities of financial and economic assistance, especially after the Lend-Lease programme began to attain full strength during 1943. Russia's main diplomatic goal at first was simply to win support to defend against the massive German invasion. With victory in sight by 1944, Moscow began creating satellite states, first of all in Poland and East Germany. The main British goals were to defeat the German threat, maintain British roles in Central and Eastern Europe, and preserve the British Empire. The British dominions and India made significant contributions to war fighting but did not have a voice in major Allied decisions. Roosevelt was hostile to the idea of the British, French and other empires, but was forced by Churchill to postpone interference in India. Roosevelt's main goal by 1943 was creation of a postwar United Nations, controlled by the Big Three, with major roles also for China and France. However China and France had only small roles in wartime diplomacy. Roosevelt was increasingly troubled by Moscow's aggressive intentions late in the war, but decided that with the United Nations in place, and his own persuasive personal relationship with Stalin, problems could be resolved after the war.

For the Axis powers diplomacy was a minor factor. The alliance of Germany, Italy and Japan was always informal, with minimal assistance or coordination. Hitler had full control of German diplomatic policies and imposed his will on his allies in Eastern Europe, and with the puppet regime in northern Italy after 1943. Japan’s diplomats had a minor role in the war, as the military was in full control. A dramatic failure was the inability of Tokyo to obtain the formulas for synthetic oil from Germany until it was too late to overcome the fatal shortage of fuel for the Japanese war machine. Practically all the neutral countries broke with Germany before the end of the war, and thereby were enabled to join the new United Nations.

The military history of the war is covered at World War II. The prewar diplomacy is covered in Causes of World War II and International relations (1919–1939). For the postwar see Cold War.

Allies

The Allies of World War II began to form in September 1939 when Poland was invaded and Britain and France declared war on Nazi Germany. With the exception of Ireland, which remained neutral throughout the war, the Commonwealth Dominions (Canada, Australia, New Zealand, and South Africa) all declared war alongside Great Britain but no other nations joined their cause. The Anglo-French Supreme War Council (SWC), established at the outset, coordinated a joint military strategy. It operated until the Battle of France concluded with a successful German invasion in June 1940, after which France surrendered and Britain and its Empire continued the fight alone against Germany.

The First Inter-Allied Meeting took place in London in early June 1941 between the United Kingdom, the four co-belligerent British Dominions (Canada, Australia, New Zealand and South Africa), the eight governments in exile (Belgium, Czechoslovakia, Greece, Luxembourg, the Netherlands, Norway, Poland, Yugoslavia) and Free France.

The Soviet Union, having first cooperated with Germany in invading Poland whilst remaining neutral in the Allied-Axis conflict, joined the Allies in late June 1941 after being invaded by Germany. The United States provided war materiel to the Allies beginning in March 1941 and officially joined in December 1941 after the Japanese attack on Pearl Harbor. China had already been in a prolonged war with Japan since the Marco Polo Bridge Incident of 1937, but officially joined the Allies during December 1941.

The Grand Alliance

The United States, the United Kingdom, and the Soviet Union formed the " Big Three" Allied powers. They were in frequent contact through ambassadors, top generals, foreign ministers and special emissaries such as the American Harry Hopkins. Relations between the three resulted in the major decisions that shaped the war effort and planned for the postwar world. Cooperation between the United Kingdom and the United States was especially close and included forming a Combined Chiefs of Staff.

There were numerous high-level conferences; in total Churchill attended 14 meetings, Roosevelt 12, and Stalin 5. Most visible were the three summit conferences that brought together the three top leaders. The Allied policy toward Germany and Japan evolved and developed at these three conferences.

Europe first

At the December 1941 Arcadia Conference US President Franklin Roosevelt and British Prime Minister Winston Churchill met in Washington, shortly after the United States entered the war. They agreed on the key elements of the grand strategy. The United States and the United Kingdom would use the preponderance of their resources to subdue Nazi Germany in Europe first. Simultaneously, they would fight a holding action and limited offensive against Japan in the Pacific, using fewer resources. After the defeat of Germany—considered the greatest threat to the UK and the Soviet Union—all Allied forces could be concentrated against Japan.

The Europe first policy remained in effect throughout the war, however the terms "holding action" and "limited offensive" in the Pacific War were subject to interpretation and modification at Allied leaders' conferences and by US senior military commanders. At Arcadia, the US agreed to send bombers to bases in England and the British agreed strengthen their forces in the Pacific. The British rejected American proposals for a "suicidal" invasion of northern Europe in 1942. Churchill pressed instead for a landing in French North Africa during 1942. With Roosevelt's support, in July 1942 Operation Torch was scheduled for later that year. Nonetheless, it was the strategic situation in the Pacific and related logistical requirements that dominated the United States' actions after its entry into the war and led to an initial focus on the Pacific. By 1944 and 1945, the balance of US resources shifted heavily towards the European Theatre as the Europe first strategy became a reality rather than just a stated objective. Even in these later stages of the war, there was intense competition for resources as operations in both regions were scaled up.

Tehran Conference

Following preparation at the Moscow Conference in October–November 1943, the first meeting of the Big Three, Stalin, Roosevelt and Churchill, came at the Tehran Conference in Iran from 28 November to 1 December 1943. It agreed on an invasion of France in 1944 (the "Second front") and dealt with Turkey, Iran, the provisional Yugoslavia and the war against Japan as well as the postwar settlement.

Yalta Conference

The Yalta Conference met in the Crimea 4–11 February 1945. It focused on postwar plans for European boundaries. The Soviets already controlled Poland. The new boundaries shifted Poland westward. Stalin was promised control of western Belorussia and western Ukraine. Poland was to gain parts of Germany. Stalin promised free elections in Poland under the auspices of a government he controlled. At Roosevelt's strong urging, Stalin agreed to enter the war against Japan three months after the defeat of Germany. It was agreed the USSR would be a member of the United Nations Security Council, with a veto, and Ukraine and Belorussia would be UN members, but not the other 12 Soviet republics. Germany was to be divided into three zones of occupation, and France was also to get a zone. In a decision that became highly controversial, all civilians would be repatriated.

Potsdam Conference

The Potsdam Conference was held from 17 July to 2 August 1945, at Potsdam, Germany, near Berlin. Stalin met with the new US President Harry S. Truman and two British prime ministers in succession—Winston Churchill and Clement Attlee. It demanded "unconditional surrender" from Japan, and finalized arrangements for Germany to be occupied and controlled by the Allied Control Commission. The status of other occupied countries was discussed in line with the basic agreements made earlier at Yalta.

The United Nations

The Declaration by United Nations formalized the Allies in January 1942. The Big Four (the United States, United Kingdom, Soviet Union and China) were joined by numerous other Allied countries who had signed the Declaration and declared war on the Axis powers. Under Roosevelt's leadership this "United Nations" alliance in 1945 became a new organization to replace the defunct League of Nations.

Dumbarton Oaks Conference

At the Dumbarton Oaks Conference or, more formally, the Washington Conversations on International Peace and Security Organization, delegations from the United States and the United Kingdom met first with delegation from the Soviet Union and then with the delegation from Republic of China. They deliberated over proposals for the establishment of an organization to maintain peace and security in the world to replace the ineffective League of Nations. The conference was held at Dumbarton Oaks from 21 August 1944 to 7 October 1944. Delegates from other nations participated in the consideration and formulation of these principles.

San Francisco Conference

The San Francisco Conference was a convention of delegates from 50 Allied nations that took place from 25 April 1945 to 26 June 1945 in San Francisco, United States. The four sponsoring countries (the United States, Britain, the Soviet Union, and China) invited the other nations and the heads of their four delegations took turns as chairman of the plenary meetings. At this convention, the delegates reviewed and rewrote the Dumbarton Oaks agreements. The convention resulted in the creation of the United Nations Charter, which was opened for signature on 26 June.

Britain–United States

Though most Americans favoured Britain in the war, there was widespread opposition to American military intervention in European affairs. President Roosevelt's policy of cash-and-carry still allowed Britain and France to purchase munitions from the United States and carry them home.

Churchill, who had long warned against Germany and demanded rearmament, became prime minister after Chamberlain's policy of appeasement had totally collapsed and Britain was unable to reverse the German invasion of Norway in April 1940. After the fall of France Roosevelt gave Britain all aid short of war. The Destroyers for Bases Agreement of September 1940, gave the United States a ninety-nine-year lease on strategically located bases in the Atlantic in exchange for the Royal Navy receiving fifty old destroyers to use against German U-boats in the Battle of the Atlantic. Roosevelt also sold (for cash) munitions that were carried away in British ships, including over half a million rifles, 85,000 machine guns, 25,000 automatic rifles, mortars, hundreds of field guns, with supplies of the necessary ammunition. The British needed these munitions to reequip the soldiers who lost all their arms when Dunkirk was evacuated in June 1940.

Beginning in March 1941, the United States enacted Lend-Lease sending tanks, warplanes, munitions, ammunition, food, and medical supplies. Britain received $31.4 billion out of a total of $50.1 billion of supplies sent to the Allies. In sharp contrast to the First World War, these were not loans and no repayment was involved.

Millions of American servicemen were based in Britain during the war, which led to a certain amount of friction with British men and intermarriage with British women. This animosity was explored in art and film, most particularly ''A Matter of Life and Death'' and ''A Canterbury Tale''. In 1945 Churchill sent the British Pacific Fleet to help the United States attack and invade Japan.

Casablanca Conference

From January 14–24, 1943 Roosevelt, Churchill and the Combined Staff met in Casablanca, Morocco. They decided on the major Allied strategy for 1943 in Europe, especially the invasion of Italy and planning for the invasion of France. At Roosevelt's suggestion they agreed on a policy of "unconditional surrender". This policy uplifted Allied morale, but it also made the Nazis resolve to fight to the bitter end. Roosevelt also tried to establish a working relationship between the two main French allies, Henri Giraud, the French high commissioner in North Africa, and General de Gaulle, leader of the Free French.

Britain

Having signed the Anglo-Polish military alliance in August 1939, Britain declared war against Germany in September 1939. This declaration included the Crown colonies and India, which Britain directly controlled. The dominions were independent in foreign policy, though all entered a state of war with Germany either immediately after the British declaration of war, or in the days after the declaration was made. After the French defeat in June 1940, Britain and its empire stood alone in combat against Germany, until June 1941. The United States gave strong diplomatic, financial and material support, starting in 1940, especially through Lend-Lease, which began in 1941. In August 1941, Churchill and Roosevelt met and agreed on the Atlantic Charter, which proclaimed "the rights of all peoples to choose the form of government under which they live" should be respected. This wording was ambiguous and would be interpreted differently by the British, Americans, and nationalist movements.

Starting in December 1941, Japan overran British possessions in Asia, including Hong Kong, Malaya, and especially the key base at Singapore, and marched into Burma, headed toward India. Churchill's reaction to the entry of the United States into the war was that Britain was now assured of victory and the future of the empire was safe, but the rapid defeats irreversibly harmed Britain's standing and prestige as an imperial power. The realisation that Britain could not defend them pushed Australia and New Zealand into permanent close ties with the United States.

India

Serious tension erupted over American demands that India be given independence, a proposition Churchill vehemently rejected. For years Roosevelt had encouraged Britain's disengagement from India. The American position was based on principled opposition to colonialism, practical concern for the outcome of the war, and the expectation of a large American role in a post-colonial era. However, in 1942 when the Congress Party launched a Quit India movement, the British authorities immediately arrested tens of thousands of activists, including Jawaharlal Nehru and Mahatma Gandhi, and imprisoned them until 1945. Meanwhile, India became the main American staging base for aid to China. Churchill threatened to resign if Roosevelt pushed too hard regarding independence, so Roosevelt backed down.

Britain and France

In spring 1939 both Britain and France formally announced they would defend the integrity of Poland. Adolf Hitler did not believe they would fight in such a faraway hopeless cause, and he invaded Poland on September 1, 1939. Britain and France declared war on September 3, 1939, but there was little they could or did do to help Poland. The Anglo-French Supreme War Council (SWC) was established to oversee joint military strategy.

= Plans for intervention in the Winter War against USSR

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The USSR launched the Winter War against Finland in November 1939. The Finns made a remarkable defence against the much larger Soviet forces. The unprovoked invasion excited widespread outrage at popular and elite levels in support of Finland not only in wartime Britain and France but also in neutral United States. The League of Nations declared the USSR was the aggressor and expelled it. "American opinion makers treated the attack on Finland as dastardly aggression worthy of daily headlines, which thereafter exacerbated attitudes toward Russia." Elite opinion in Britain and France swung in favor of military intervention. Winston Churchill, as head of the Royal Navy, and French Premier Paul Reynaud were the chief advocates. It came when there was a military stalemate on the continent called the " Phony War". Months of planning at the highest civilian, military and diplomatic levels in London and Paris, saw multiple reversals and deep divisions. Finally the British and French agreed on a plan that involved uninvited invasions of neutral Norway, Sweden, Iceland, and Denmark's Faroe Islands, with the goals chiefly of damaging the German war economy and also assisting Finland in its war with the Soviet Union. An allied war against the Soviet Union was part of the plan.

The actual Allied goal was not to help Finland but to engage in economic warfare against Germany by cutting off shipments of Swedish iron ore, which they calculated would seriously weaken German war industry. The British Ministry of Economic Warfare stated that the project against Norway would be likely to cause "An extremely serious repercussion on German industrial output ... and would in any case have a profound effect on the duration of the war." The idea was to shift forces away from doing little on the static Western Front into an active role on a new front. The British military leadership by December became enthusiastic supporters when they realized that their first choice, an attack on German oil supplies, would not get approval but this plan would win strong support. The poor performance of the Soviet army against the Finns strengthened the confidence of the Allies that the invasion, and the resulting war with Russia, would be worthwhile. However the civilian leadership of Neville Chamberlain's government in London drew back and postponed invasion plans. The neutrals refused to cooperate. Meanwhile, Finland was overwhelmed and gave in to Moscow on 13 March 1940 and the plan was postponed. War plans against the USSR were dropped and the new goal was to mine the Norwegian coast to prevent the passage of ships carrying iron ore from northern Norway. There were more delays and when mining operations finally started on 9 April it was too late—the Germans hours before had invaded Norway and had the upper hand in the Norwegian Campaign.

= German invasion 1940

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When Germany began its attack on France in May 1940, British troops and French troops again fought side by side, but defeat came quickly. The Royal Navy evacuated 198,000 British and 140,000 French soldiers in the Dunkirk evacuation in late May/early June 1940. Tens of thousands of tanks, trucks and artillery guns were left behind, as well as countless radios, machine guns, rifles, tents, spare parts and other gear. The new British Prime Minister, Winston Churchill, pledged that the United Kingdom would continue to fight for France's freedom—even if it must do so without France. After Mers el Kebir, Britain recognised Free France as both its ally and the only legitimate French government.

In contrast, the United States formally recognized and established diplomatic relations with Vichy France (until late 1942) and avoided formal relations with the exiled government of de Gaulle's and it's claim to be the one and only legitimate government of France. Churchill, caught between the US and de Gaulle, tried to find a compromise.Milton Viorst, ''Hostile allies: FDR and Charles de Gaulle'' (1967)David G. Haglund, "Roosevelt as 'Friend of France'—But Which One?", ''Diplomatic History'' (2007) 31#5 pp: 883–908.

Britain and the Soviet Union

The Anglo-Soviet Agreement was signed in July 1941 forming an alliance between the two countries. This was broadened to a political alliance with the Anglo-Soviet Treaty of 1942.

In October 1944 Churchill and his Foreign Minister Anthony Eden met in Moscow with Stalin and his foreign minister Vyacheslav Molotov. They planned who would control what in postwar Eastern Europe. They agreed to give 90% of the influence in Greece to Britain and 90% in Romania to USSR. USSR gained an 80%/20% division in Bulgaria and Hungary. There was a 50/50 division in Yugoslavia, and no Soviet share in Italy.

Middle East

= Iraq

=

Iraq was an independent country in 1939, with a strong British presence, especially in the oil fields. Iraq broke relations with Germany but there was a strong pro-Italian element. The regime of Regent 'Abd al-Ilah was overthrown in 1941 by the Golden Square pro-Italian army officers, headed by Rashid Ali. The short living pro-Nazi government was overpowered in May 1941 by British forces in a quick campaign and the Regent returned to power. Iraq was later used as a base for allied attacks on Vichy-French held Mandate of Syria and support for the Anglo-Soviet invasion of Iran.

= Iran (Persia)

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In 1939 the ruler of Iran was Reza Shah. He was a modernizer who had little use for traditional religion, but collaborated with the Germans. Iran proclaimed neutrality when the war began in 1939. British and Soviet forces occupied Iran in August 1941, deposed the Shah, and installed his son Mohammad Reza Shah Pahlavi. Iran, with a largely rural population of 13 million, had oil wells and became a major route for shipping military supplies from the US to the Soviet Union.

At the Tehran Conference of 1943, Stalin, Roosevelt and Churchill issued the Tehran Declaration that guaranteed the postwar independence and boundaries of Iran. However, when the war actually ended, Soviet troops stationed in northwestern Iran not only refused to withdraw but backed revolts that established short-lived, pro-Soviet separatist national states in the northern regions of Azerbaijan and Iranian Kurdistan, the Azerbaijan People's Government and the Republic of Kurdistan respectively, in late 1945. Soviet troops did not withdraw from Iran proper until May 1946 after receiving a promise of oil concessions. The Soviet republics in the north were soon overthrown and the oil concessions were revoked.

Commonwealth

As the Statute of Westminster 1931 was not yet ratified by the parliaments of Australia and New Zealand when the King declared war against Germany on 3 September 1939, the declaration also applied to them. As the Statute of Westminster was already in effect in Canada and South Africa, they issued their own declarations of war against Germany in September 1939. South Africa issued a formal declaration of war against Germany on 6 September, following debates in the South African parliament between the pro-British faction, led by Jan Smuts, and supporters of neutrality, led by Albert Hertzog. The Canadian declaration of war on Germany was issued on 10 September. However, as opposed to South Africa, there was little debate over the issue. Shortly after the British declaration of war on 3 September, the Canadian Prime Minister William Lyon Mackenzie King made a radio address to the Canadian public, stating that he stands with Britain, and would recommend for a declaration of war to the Canadian Parliament. The parliamentary vote on the declaration was delayed by Mackenzie King, partly as a symbolic statement of the dominion having an autonomous foreign policy.

Britain generally handled the diplomatic relations of the Commonwealth nations. Canada hosted top level meetings between Britain and the US (the First and Second Quebec Conference), although Canadian representatives only participated in limited bilateral discussions during those summits. As opposed to World War I, the British government, and the governments in the dominions did not form an Imperial War Cabinet, although the establishment of one was proposed by the Australian government in 1941. The proposal was rejected by both Churchill, and Mackenzie King; the former unwilling to share powers with the dominions, and the latter wanting to maintain the appearance that the dominions have an autonomous foreign policy. Mackenzie King also viewed the formal establishment of an Imperial War Cabinet as unnecessary, believing that contemporary methods of communication and the appointment of high commissioners to the other realms, had already provided the governments with an "invisible imperial cabinet".

= Australia

=

During the war, Australia felt abandoned by London and moved to a close relationship with the US, playing a support role in the American war against Japan. Australian Prime Minister John Curtin stated, "I make it clear that Australia looks to America, free of any pangs as to our traditional links or kinship with the United Kingdom." US President Roosevelt ordered General Douglas MacArthur to move the American base from the Philippines to Brisbane, Australia. By September 1943, more than 120,000 American soldiers were in Australia. The Americans were warmly welcomed but there was some tensions. MacArthur worked very closely with the Australian government and took command of its combat operations.

Fighting continued throughout Southeast Asia for the next two years. MacArthur promoted a policy of " island hopping" for his American troops while he suggested that the Australian troops should continue clearing and rounding up the Japanese from New Guinea, New Britain, Borneo, and Bougainville.

The Canberra Pact of 1944 between Australia and New Zealand was criticised in the United States.

= Canada

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Canada's declaration of war drew criticism from some American isolationists, with noted American isolationist Charles Lindbergh attacking Canada for drawing the Western Hemisphere "into a European war simply because they prefer the Crown of England", to independence of the Americas. However, most American isolationists who were critical of Roosevelt's for assisting the British, were unable to levy the same criticism for assisting Canada. After the fall of France, concerns that the British may be defeated grew in North America, prompting military meetings between Canada and the United States on July 1940. On 16 August 1940, the two countries entered into the Ogdensburg Agreement, which outlined plans for the mutual defence of North America, as well as the establishment of the Permanent Joint Board on Defense. Initially, the plans for mutual defence included the Americans assuming command of Canadian forces in the event of an invasion; however, as the situation improved for the British in 1941, revised defence plans saw the Canadian government refuse to defer command of its forces to the Americans.

The need to develop necessary facilities in northern Canada saw 33,000 American soldiers and civilians working in that region during the war, in order to build the Alaska Highway