neither England or france would have amounted to a hill of beans had not the US supplied them. Neither would the Russians. The US could not have cared less if Hitler had killed every last Russian. in fact, many would have at least cheered and quite a few would have sent him money.
Most US industrialists like Henry Ford and JD Rockefeller, wanted the US to make a deal with Hitler to fight the greater enemy - Communist Russia, as did the bankers, because all else aside, fascism is compatible with capitalism, while communism could lead to confiscation and nationalization of their assets.