I will concede WWI on this ground; my analysis is speculation based upon the conditions at the time. My hypothesis is that with the Russians out of the war that the Germans could have defeated the UK and France as they had been able to figh them to a stalemate while fighting on two fronts.

What the US did was to show the Germans that they would not have the 'last million men' and that they would be at a severe disadvantage in production. This is my speculation, but I think is accurate. I will concede the point reluctantly.

On the issue of WWII, I think that it was American production that 'won' the war. I further argue that the Brits would have been greatly diminished as a fighting force without the US feeding the population or suppling arms and munitions. So much so that the Germans would have been able to move enough divisions to defeat teh Russians.


http://www.army.mil/cmh-pg/books/amh/AMH-19.htm

"He also proclaimed American neutrality in the war, but at his urging Congress presently gave indirect support to the western democracies by ending the prohibition on munitions sales to nations at war embodied in the Neutrality Act of 1937. British and French orders for munitions in turn helped to prepare American industry for the large-scale war production that was to come. "

"On the eve of France's defeat in June 1940 President Roosevelt had directed the transfer or diversion of large stocks of Army World War I weapons, and of ammunition and aircraft, to both France and Great Britain, and after France fell these munitions helped to replace Britain's losses in the evacuation of its expeditionary force from Dunkerque. More aid to Britain was forthcoming in September when the United States agreed to exchange fifty over-age destroyers for offshore Atlantic bases, and the President announced that henceforth production of heavy bombers would be shared equally with the British. An open collaboration with Canada from August 1940 onward led to a strong support of the Canadian war effort, Canada having followed Great Britain into war in September 1939. The foreign aid program culminated in the Lend-Lease Act of March 1941, which swept away the pretense of American neutrality by openly avowing the intention of the United States to become an "arsenal of democracy" against aggression. Prewar foreign aid was nonetheless a measure of self defense; its fundamental purpose was to help contain the military might of the Axis powers until the United States could complete its own protective mobilization."

http://www.onwar.com/articles/f0302.htm

"This analysis shows that while by 1942 there was a substantial Allied economic advantage, measured in GDP, this did not exist at the beginning of the war in 1939. In fact for a period of time the Axis commanded greater GDP than the Allies. Suggesting that the Allies had a GDP superiority from the start is wrong and misses the dynamics of World War II. It is worth noting that from a lead of 1.25 in 1939, the Allies were reduced to a miserable 0.38 by 1941. There was nothing preordained about the recovery of GDP that followed. It is unreasonable to believe that Allied decision makers were particularly confident of economic dominance until well into 1942, regardless of their public pronouncements."

http://www.usmm.org/ww2.html

"Had these ships not been produced, the war would have been in all likelihood prolonged many months, if not years. Some argue the Allies would have lost as there would not have existed the means to carry the personnel, supplies, and equipment needed by the combined Allies to defeat the Axis powers. [It took 7 to 15 tons of supplies to support one soldier for one year.] The U.S. wartime merchant fleet. . . constituted one of the most significant contributions made by any nation to the eventual winning of the Second World War...."

http://www.usmm.org/quotes.html#anchor198704

"The only thing that ever really frightened me during the war was the U-boat peril.

http://www.naval-history.net/WW2CampaignsAtlanticDev.htm
1939
Total Losses = 402 British, Allied and neutral ships of 1,303,000 tons (186,000 tons per month)
1940
Total Losses = 878 British, Allied and neutral ships of 3,441,000 tons (382,000 tons per month)
1941
Total Losses = 1,299 British, Allied and neutral ships of 4,329,000 tons ( 361,000 tons per month)

Note that these losses are losses of goods and material for the allied war effort.

http://uboat.net/allies/documents/lend-lease.htm
"When the war had ended the Lend-Lease programme had extended over $41 billion in aid to more than 40 nations (some sources say the aid was as high as $50 billion). Britiain got the biggest share or roughly $30 billion and the Soviets about $11 billion. China got $1 billion.

Less than $10 billion of that aid was ever repaid, making this appear more like the donation and support it really was."