1940: The British Security Coordination, or BSC, is discovered by the US public. Rapidly spiraling into an highly damaging diplomatic incident, helped by the opposition fully taking advantage of it. Willkie takes the Presidency, and Anglo-American relations take a dive, which will only be exasperated by coming events.
1941: Pearl Harbor occurs, along with the seizure of many US islands, as the US is caught off guard. This weakens the initial US response, and causes worries in Australia.
Anti-British sentiment in the US remains, causing strategic difficulties with the campaign in the Pacific.
1942: The UK shifts forces out of Asia to deal with Nazi Germany, causing Australia to feel further isolated.
1943: Full force of the US military is beginning to be felt, and they begin to court Australia, who feels abandoned by the United Kingdom. The UK, meanwhile, has finally pushed the Nazis out of Africa, however is near total exhaustion from a lack of financial support.
1944: The Soviets finally get back to their 1940 borders, however lack the resources or manpower to continue onwards.
The UK signs a cease-fire with Nazi Germany and Fascist Italy, as it lacks the resources to continue the war against either. Currently, it has massive debt, and is unable to pay for war goods from the United States.
The United States makes much progress against Japan, with the help of Australia, with which it almost outright annexes many UK owned islands. This fuels a further Anglo-American break in relations, however the UK can do nothing to contest this.
1945: Japan is finally starved into submission by the United States, and finally surrenders.
1947: Hitler finally dies, sending Nazi Germany, and the rest of its empire into a civil war for power. The United Kingdom re-enters the war, entering Italy to destroy a Fascist power. The USSR begins to tentatively take back its 1939 borders, however with extremely limited success because of economic limitations.
Meanwhile, the United States tests its first nuclear bomb, and finalizes relations with Australia in regards to Southeast Asia.