We seem to have a couple of threads that have strayed into one however I will respond here with both answers. With respect to the biggest mistake, if Hitler had not declared war on the US, Roosevelt would have only been allowed to deal militarily with the Pacific war against the Japanese. Hitlers declaration took that problem out of Roosevelts hands. 1- Roosevelt would have declared war on Germany. 2- That would not have changed by much, anyway. Since in 1941 the US was years away from developing the capabilities of attacking Europe. With respect, the quoting of bare GNP percentage figures is ridiculous and somewhat insulting. Without screwing those figures down into what was sent and how it enabled Russia to pull up stumps, survive the crucial process of moving east and then being able to concentrate their production more fully into certain crucial areas makes your argument ambiguous to say the least. Russia's scorched earth policy denied Germany resources however it affected Russian manufacturing as well in the short term. The comprehensive supply of food products and "finished" materials allowed Russia to commence production immediately in many areas by taking out one level of the manufacturing processes at those crucial times. Sure, but if they sent more it would be better. It was a mistake sending only 17 billion of lend-lease to Russia. They should have sent more. This is clearly another shooting from the hip comment that was not possible to achieve. Shipping, the elements and scourge of distance are just a few of the prohibitive factors that would never have seen this level of volume achievable. The US could make more ships. The US could have allocated more ships to lend-lease supply to Russia. And yes, they could have supplied more materiel to the USSR. And the fact that they did not was a mistake.