US Entry into the Second World War: How “Neutrality” Ended at Pearl Harbor

«If we see that Germany is winning the war we ought to help Russia, and if Russia is winning we ought to help Germany, and that way let them kill as many as possible.»

Harry Truman, US senator, June 1941 (The New York Times, 24 June 1941)

What the textbooks leave out

Before talking about America "fighting fascism", remember who grew it. In the 1920s American banks poured billions of dollars into Germany under the Dawes and Young plans, and after the 1929 crash the credit collapsed. Unemployment and poverty handed the country to the Nazis. It is not the only reason Hitler came to power, but without American money the German economy and German revenge would not have risen so fast.

American business stayed in Germany under Hitler. General Motors owned Opel, Ford kept a plant in Cologne, Standard Oil shared patents with IG Farben, and Torkild Rieber’s Texaco supplied the Francoists with fuel, as I wrote. In 1938 Henry Ford received from the Reich the Grand Cross of the German Eagle, the highest order for foreigners. American-owned factories in Germany kept working through the war years, and historians write that after the war the concerns sought compensation for bombed workshops. The assets of the Union Banking Corporation, where Prescott Bush was a director, were seized by the US only in October 1942 under the Trading with the Enemy Act.

Now look at the politics. In June 1941 Senator Harry Truman said what is quoted above. The second front that Stalin had demanded since 1942 was opened only on 6 June 1944, when the outcome of the war in the East was already decided.

I know of no document with a plan to "drag out the war", and I will not invent one. But this is how I read the facts. Entry into the war was presented as a crusade against fascism, while in practice Washington waited for Germany and the USSR to bleed each other. Before that Germany had been a convenient weapon against Moscow, one that later had to be "switched off". Everyone will draw their own conclusion, but all these facts are American.

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They built rockets, experimented on human beings and ran intelligence against the USSR, and after the war they got jobs in the US. For what merit?

In my view this is indirect evidence that the Nazi machine was for Washington an instrument against Moscow. I know of no document saying that the US "brought Hitler to power to attack the USSR", but the choice of people after 1945 speaks for itself.

Whom the US took in after the war

• Wernher von Braun — SS major, creator of the V-2 rocket, which was built with the slave labour of prisoners (about 20,000 died at the Mittelwerk plant). In the US: director of NASA’s Marshall Space Flight Center, designer of the Saturn V.
• Arthur Rudolph — director of the same Mittelwerk plant. In the US: head of the Saturn V project, a NASA award; in 1984, after a US Justice Department investigation, he gave up citizenship and left for West Germany.
• Kurt Debus — SS officer who ran V-2 launches against London and Antwerp. In the US: first director of the Kennedy Space Center.
• Eberhard Rees — Braun’s deputy at Peenemünde. In the US: director of NASA’s Marshall Center.
• Walter Dornberger — general, head of the V-2 programme. In the US: vice-president of Bell Aircraft, worked for the Air Force.
• Hubertus Strughold — head of Luftwaffe aviation medicine; his institute is linked to experiments on Dachau prisoners (his personal involvement is disputed). In the US: "father of space medicine"; until 2012 an Air Force award and library bore his name.
• Kurt Blome — head of the Reich’s biological weapons programme, acquitted at Nuremberg. In the US: a contract with the Army Chemical Corps.
• Reinhard Gehlen — general, chief of intelligence on the Eastern Front. From 1946 the US (the Army, then the CIA) funded his organisation; later he became the first head of West German intelligence (BND).
• Franz Six — SS brigadier, led an advance detachment of an Einsatzgruppe in the USSR; left prison in 1952. Worked for Gehlen’s organisation.
• Wilhelm Höttl — SD officer who worked with Eichmann in Hungary. After the war he worked for American counterintelligence and for Gehlen.
• Klaus Barbie — Gestapo in Lyon, the "Butcher of Lyon". In 1947 he was recruited by US Army counterintelligence, in 1951 he was smuggled to Bolivia; France sentenced him to life in 1987.
• Otto von Bolschwing — SS officer, Eichmann’s aide. The CIA brought him to the US, he received citizenship; proceedings to strip it began in the 1980s and he died before trial.
• Franz Halder — Chief of the Army General Staff, one of the authors of the plan to attack the USSR. In the US: led a group of former Wehrmacht officers in the US Army Historical Division, awarded a civilian medal in 1961.
• Adolf Heusinger and Hans Speidel — Wehrmacht generals. In NATO: Heusinger chaired the Military Committee (1961–1964), Speidel commanded NATO land forces in Central Europe (1957–1963).
• Otto Ambros — IG Farben, builder of the plant at Auschwitz-Monowitz; convicted at Nuremberg, released in the early 1950s. In the US: adviser to W. R. Grace and Dow Chemical.
• Erich Traub — virologist who worked on the Reich’s biological weapons. After the war the US brought him over under Paperclip and he worked for the Office of Naval Research.

Operation Paperclip: more than 1,600 German specialists. The US Army Historical Division: about 700 former Wehrmacht officers. According to the US Justice Department, mentions of Nazi convictions were scrubbed from their files. The list is incomplete: I kept only those whose service to the US or on American money is confirmed by documents.

The US entry into the Second World War came on 8 December 1941, the day after Pearl Harbor. But America had stopped being neutral long before that. From 1939 Roosevelt helped, step by step, the countries fighting Germany. I have long considered this story the best textbook on the word “neutrality”: it covers a choice that has already been made.

Let’s trace how it went, step by step, and why Pearl Harbor was sudden only for the public.

The neutrality that did not exist

After the war in Europe began in September 1939, Congress allowed arms trade on “cash and carry” terms. In 1940 the US gave Britain destroyers in exchange for bases, which I wrote about in my article on the “destroyers for bases” deal. In March 1941 the Lend-Lease Act took effect. It allowed weapons to be supplied to allies on credit.

Moreover, the American fleet escorted convoys in the Atlantic. In September 1941 Roosevelt ordered ships to shoot German vessels on sight. Formal neutrality was kept, while in fact the US was already being drawn into the conflict.

The US entry into the Second World War: 7–11 December 1941

On 7 December 1941 Japan attacked the American base at Pearl Harbor. More than 2,400 Americans died, and eight battleships were damaged or sunk. The next day Congress declared war on Japan. Jeannette Rankin alone voted against.

The decisive step was taken by Germany itself. On 11 December Hitler and Mussolini declared war on the US, and Congress answered in kind the same day. So the US found itself in two wars at once: in the Pacific and in Europe.

Why this choice was not accidental

Pearl Harbor was the occasion but not the only cause. Before it, American public opinion was against war. The attack removed the domestic argument instantly. Moreover, historians argue about whether Washington could have avoided the conflict with Japan. This is above all connected with the oil sanctions, which I write about in my article on the oil embargo against Japan.

What is beyond dispute is something else: by 1941 the US was preparing for war economically and politically. Factories were switching to military orders, and the draft had begun back in 1940.

The outcome of the war for the US

After April 1945 the war was finished by Harry Truman. In August he ordered atomic bombs dropped on Hiroshima and Nagasaki. The war ended on 2 September 1945 with Japan’s surrender. The US also lost about 405,000 people but came out of it as the world’s strongest power.

This differed greatly from the experience of the previous war. More in my article on the US entry into the First World War.

What became the norm after 1945

The main result is not the victory but the habit: a president can prepare the country for war without a vote and present it as defence. The US honed this habit well on Latin America, as you can read in the piece on the military government in Cuba.

Lend-Lease, convoys and the Reuben James: the last steps to war

Curiously, the Lend-Lease Act was passed on 11 March 1941, and in August Roosevelt and Churchill signed the Atlantic Charter. Therefore by autumn American ships were in effect fighting in the Atlantic. For example, on 4 September 1941 the destroyer Greer clashed with a German submarine, and on 31 October the destroyer Reuben James was lost, taking about a hundred lives.

Thus by December the US was already shooting and losing people, and Pearl Harbor merely turned a silent war into a declared one. Moreover, the 1940 Selective Training and Service Act introduced the first peacetime draft. The overall picture is in the reference article on the US in the Second World War.

The US entry into the Second World War: the result for the world and for America

Judged by its result, the US entry into the Second World War changed the balance of power for good. For example, American industry produced tens of thousands of aircraft and hundreds of thousands of trucks during the war, and the dollar became the world’s main currency. Moreover, after 1945 the US acquired dozens of bases around the globe. Therefore “neutrality” turned out for them to be a profitable pause before the leap.

Thus the war fixed America’s image as the “arsenal of democracy”. However, that image sat badly with the interventions in Latin America and Asia. This gap between words and deeds is clearly visible in my article on the intervention in Guatemala.

Nothing has changed: war without a declaration

Entering a war used to require a vote in Congress. Today strikes often go ahead without it, and the words “limited operation” have replaced the word “war”.

Libya, 2011. Obama began the operation without Congressional authorisation. He also held that it was not “hostilities” in the sense of the law.

Syria, April 2017. Trump hit the Shayrat air base with missiles without Congress’s approval.

Iran, June 2025. On 22 June the US struck Iran’s nuclear sites at Fordow, Natanz and Isfahan. Congress had not voted beforehand.

Iran, February 2026. On 28 February the US and Israel started a new war and killed Supreme Leader Ali Khamenei.

Venezuela, January 2026. On 3 January the Americans struck Caracas and seized President Maduro. Congress was not asked.

The US entry into the Second World War was legal and quick, but it had been prepared for years. Neutrality covered help for one side. The US applied the same tactic earlier too, for example in Central America: see the article on the invasion of Honduras.