Someone needs to look into Lend-Lease. The Russians were getting their asses pushed back hard until US provided weapons and ammunition started to flood into the country. It was only with the US's help, combined with German tactical and strategic errors that turned the tide on that front.
As to the European and African front's, the Germans pushed the Brits half way across Africa. It took Monty to turn that tide, and between him and Patton, they pushed the Germans and Italians out of Africa, across Sicily, and into the boot of Italy. Lets keep in mind that Patton's 7th army took the brunt of the Sicily campaign capturing both Palermo and Mesina. Patton and Monty resumed their rivalry in Europe and pushed the Germans back, hard. The only reasons the Russians made it to Berlin, was due to politics, as the US was within reach well before the Russian advance came up, a fact that pissed Georgie off to no end.
The war was hardly over when the US entered. When they did, the Brits had been holding on by their iron willpower, France was a conquered country, and most of Northern Africa was under Axis control. A year later, the map was quite different, with Italy on the wires, and Germany in retreat.
American aid in WW2 was huge.
A total of $50.1
billion (equivalent to nearly $700 billion at 2007 prices) worth of supplies were shipped: $31.4 billion to Britain, $11.3 billion to the Soviet Union, $3.2 billion to France and $1.6 billion to China. Reverse Lend Lease comprised services (like rent on air bases) that went to the U.S. It totaled $7.8 billion, of which $6.8 billion came from the British and the
Commonwealth. Apart from that, there were no repayments of supplies that arrived before the termination date, the terms of the agreement providing for their return or destruction. (Supplies after that date were sold to Britain at a discount, for Ā£1,075 million, using long-term loans from the U.S.) Canada operated a similar program that sent $4.7 billion in supplies to Britain and Soviet Union.
[2]
http://en.wikipedia.org/wiki/Lend_lease
On a side note, regarding my own personal disdain for the French.
The stories I've heard from several veterans, was that when the US forces were leaving France at the wars end, the French would line the streets and make obscene gestures, and tell them to "get out". So grateful were they that American's shed their blood to save their country when they themselves couldn't, that they would shower the trains with rocks in joy. So, to me, while the US can say thank you to the French for loaning us some money, and selling us some guns back in our infancy, we have more than repaid that debt, with high interest by our own sacrifices in recovering and restoring their own country to them. It also I am sure chaffs them terribly to owe the British the same debt for saving their collective asses, though they seem to forget that often I hear.