The USA was already making money from both sides of the war in Europe. That was mostly the reason they didn’t enter it until Japan bombed them because Japan didn’t like having their fuel supplies cut off by the USA because the USA thought the USA should be the only ones to expand an empire into the Pacific. Following that they wanted support for their retaliation to Japan’s retaliation to their retaliation to Japan’s expansion into the Pacific so they picked a side in Europe (probably the side who owed them the most money) and entered the war against the Nazis.