You just have to look at the comment made by MARTY MANN:
Yeah I hate it for Japan but remember those idiots started World War 2. They bombed Pearl Harbour.
Was it not the Germans who invaded Poland in 1939 that started World War 2?
How the Americans forget the years before their involvement.
Interesting, and on the face of it correct. But actually it could be argued WW2 was born out of the Great War and then the Versailles Treaty, which made the last World War inevitable as recognised by some in 1919. As for the Japanese bombing Pearl Harbour at 0755 on the 7th of December 1941, thank God they did. It resulted in the USA coming into the war that did save the British situation, and gave us all the added bonus of Hitler's Germany declaring war on the United States when already engaged in operation BARBAROSSA in Russia!

What luck that all was, and it was the most defining moment of the war which spelt the eventual demise of the Nazis

God bless America, and please never insult an American in front of me!

Lizzie, Hitler was financially and resourcefully finished after they go deep in Russian lands.. Imo, Americas entering the scene may only have the effect of shortening the war period but remember they rejected to declare war to Germany in the hardest days of Britain when they were fighting with Germany in the skies and under bombardement.. 
We know all that only too well Cem! But President Roosevelt did as much as he politically could to assist in meeting some of Churchill's pleas for armaments and supplies, albeit at much cost to Britain!

However, it must be remembered that isolationism existed in the majority throughout America, and they did not want to get embroiled in yet another European conflict. The founding fathers had left Britain and Europe to get away from all that!
However 7th December 1941 was THE turning point, and in fact Britain would have struggled to win back Europe from the Nazis without American help. The war would have dragged on for many years more than it did without the industrial might, and pure manpower numbers of the USA. There was no guarantee that the USSR would overcome the Nazis, but the American involvement kept very much alive the Allies offensive on the Western and Southern fronts. Britain had kept the Nazis at bay from their 'fortress' that would become the base for the future fight back. Without American might however, Britain would not have had the resources to continually attack German interests, and then eventually push the Nazis back from North Africa, Sicily and Normandy. Britain would also have not been in a position to supply Russia with much needed supplies without the feed from the USA.
No, the USA involvement, as much as sometimes I wish it had been different as it resulted in Britain owing £3 billion by 1945, was crucial in securing victory in Europe by May 1945. Then of course the USA was also crucial, indeed the absolute key, to the defeat of the Japanese. The British would not have secured such a victory by themselves.
But that is all history, and today both Germany and Japan are very different countries, with the latter going through a disaster at least as challenging as WW2 itself