Breakdown of Grand Alliance 1945-7

Roosevelt died, 12 April 1945.

He was replaced by Harry Truman, a hardliner anti-Communist who wanted the USSR to declare war against Japan, saving hundreds of thousands of lives. He would consider lend lease, ($50 billion was given to allies during war in hopes of eventually receiving this back), to force concession from Yalta AND cooperation. 

He was less experienced than Roosevelt. 

He became increasingly concerned over Poland.

Daniel Yergin argued that he could not see rationality in Russia's quest for security, and only had a storybook view of history.

In August 1944, the US, UK, and USSR met at Dumbarton Oaks, near Washington, to discuss the fate of the UN. 

It was decided there would be General Assembly with a Security Council of the UK, US, USSR, and China, and later France, (1945), to veto decisions made by the Asssembly. 

There were disagreements over the USSR's permanent membership, and if it should have rights to veto decisions made by another member of the UN in disagreement. They wanted the 16 member republics of the USSR to be in the UN. At San Francisco, April 1945, it was decided that only Belarus and Ukraine would be members of the assembly, as well as the USSR. 

It is believed Potsdam was delayed until Truman could test the atom bomb on 16 July 1945 to intimidate Stalin. 

On 17 July 1945, the Potsdam Conference commenced outside Berlin. 

Stalin, intimidated by the atom bomb, ordered the USSR to advance it's nuclear development programme, but it had little effect in Eastern Europe policy. 

By 26 July, Churchill was replaced by Clement Atlee of the Labour Party. 

It was agreed that Germany should be demilitarised, with denazification and punishment of war criminals. 

ACCs were also agreed on. 

Germany was to have an ACC with miliary commanders from four occupying powers. The Soviets demanded the commanders control separate zones to prevent outvoting, and prevented exercise of control over all of Germany. Central departments would later be established for finance, trade, and industry.

The USSR had been devastated by war and wanted massive reparation, but the Allies needed a strong German economy, not wanting to help pay for imports of raw materials and food. 

A compromise was made that the USSR and USA would extract reparations from their own zones, and Britain and the USA would grant 10% to the Soviets and 15% further in exchange for food and raw materials from the USSR.

At Yalta the Western powers agreed Poland should win: 'substantial accessions of territory' from Germany. However, they criticsed the Oder Neisse Line between Oder and Western Neisse rivers to be too much. 

The Soviets occupied Poland so not much could be done, and recognised the line, pending a final decision at a future peacetime conference. They hoped this would make the Soviets more flexible with regards to German reparation and democratic government in Poland.

At Potsdam, the Council of Ministers, China, UK, US, USSR, and France, were to negotiate peace treatiers with former Axis countries Italy, Romania, Hungary, Finland, Bulgaria, and Hungary, and a peace settlement with Germany once a German government was established by Allies.

On 16 July, 1945, the first atomic bomb was tested in Alamogordo, New Mexico, and was shown to be very destructive. It was used against Hiroshima on 6 August, killing half its population and flattening the city. Nagasaki was bombed three days later, killing 40,000, while Manchuria, a north-east region in China occupied by the Japanese, was invaded by the USSR. Japan had to surrender. 

The US had also considered using their nuclear monopoly, or having the UN decide the fate of the bomb. John Lewis Gaddis considered with the bomb, the balance of power was drastically altered, and the US could potentially impose its will on the rest of the world.

Advisors such as Dean Acheson, deputy secretary of state, considered the lead temporary, as shown in September 1945, when espionage missions in Canada and USA were revealed.