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Why did the Allies find it hard to agree about a Second Front in the Second World War?

A British fishing trawler rescuing Allied troops during the evacuation of Dunkirk (this is a screenshot from the 1943 United States Army film, ‘Divide and Conquer’ (Why We Fight On) directed by Frank Capra) (Wikimedia Commons)

In the early stages of the Second World War Germany and its allies had the upper hand. German forces drove through Poland and northern Europe in 1939 and 1940. By May of 1940 the British Expeditionary force, sent to support the French Army, had been driven back and had to be evacuated from Dunkirk.

There was a real concern that the Germans would drive on and invade Britain as well, but for a range of reasons this didn’t happen. Once the threat of invasion had receded, the Allies began planning for the invasion of Europe. It was the only way the war could be won, but it would take time for Britain to rebuild its forces and be in a position to defeat Hitler.

In one of the key moments of the Second World War, Hitler’s forces invaded the Soviet Union in May 1941. This proved to be the decisive front of the war with the vast majority of German casualties being suffered on the Eastern Front. It was a huge and brutal campaign and caused immense suffering and loss in the USSR.

German soldiers fighting in the Russian heartland in June 1941
(Wikimedia Commons;
Bundesarchiv, Bild 146-1974-099-19 / Kempe / CC-BY-SA)

British forces, Royal Marine Commandos, move inland from Sword Beach on the Normandy coast during the invasion of France in June 1944. (Photo by Hulton Archive/Getty Images)

Once the US entered the war in December 1941, Soviet leader Stalin demanded a Second Front to take the pressure off the Soviet Armies who were, he felt, fighting Germany alone. There were tentative plans for invasions in 1942 and in 1943 before it finally happened in 1944 in the form of Operation Overlord (more commonly known as D-Day).

The U-Boat campaign was a serious restriction on how fast American forces could build up in Britain and prepare for the invasion of Europe. Once the German submarine threat was largely overcome, in 1943, it became easier to build up the resources needed to defeat Hitler.

However, there were serious disagreements between Britain, US and the USSR over where, and when, to attack the Germans. Churchill was opposed to an all-out invasion of France. He preferred to defeat the Nazis via North Africa, Italy, the Aegean and the Balkans, which he thought would lead to fewer casualties. By contrast, US military commanders were much more in favour of an outright assault on France at the earliest opportunity.

Perhaps Churchill took a strategic view of the likely shape of the post-war world, whereas Roosevelt wanted victory as quickly as possible. Britain was war-weary and financially bankrupt, whereas the US was an economic superpower and rapidly expanding its forces and its world view. The bombing campaign was designed to weaken the Germans and make defeating them easier. And of course there were the Japanese to deal with too – there were so many demands on Allied troops and resources.

The Churchill Archive contains lots of materials about the planned invasion of Europe. A topic search for ‘Overlord’ (the codename for the invasion of Europe in 1944) produces 171 results so the selection here is only a tiny fraction of what’s available. Are they characteristic of the debates over the invasion? And do they help explain the differences between British and American approaches to defeating Hitler?

Investigation page

The sources

Notes for teachers

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How Churchill was bullied into D-Day
‘Fault or blame is mine alone’ – Eisenhower
D-Day Museum: countdown to D-Day
Should D-Day have happened earlier?
‘Churchill as Strategist in World War Two’, Jeremy Black*