Before the war America was isolationist with good reason.
Furthermore, France and Britain appeased Hitler when he could have been stopped, first in the Rhineland in 1936 and then in Czechoslovakia in '38. In fact, Hitler had ordered his forces to withdraw if confronted by the Anglo-French.
Meanwhile, the ambassador pointedly omitted U.S. loans and lend lease. In fact, the American-built Curtis Hawk was France’s most important fighter, scoring one-third of credited aerial victories in 1939-40. And America’s role in the Battle of the Atlantic, which cost thousands of U.S. merchant sailors, began in September 1939.
In 1939 the U.S. military counted 335,000 men—less than 3 percent of the total needed to win the war—and the 1940 draft act passed Congress by one vote. Yet because of our non-neutral aid to the Allies, Hitler was eager to declare war on us after Pearl Harbor.