France was under the boot for eighteen months before the US even entered the war, so we might wonder how altruistic the actions of the latter were.
You need to be careful who you blame for that.
FDR wanted the USA to pitch in because he recognised that the Nazis were a threat to the whole world not just Europe. Unfortunately he had to deal with his very own Nazi sympathisers at home. There was a core group of very of prominent and very wealthy American businessmen who had a lot to gain from helping and supporting the right wing regimes in Europe for the twenty or so years prior to WW2. They supported Franco during the Spanish Civil War of 1936 with materiel. They also supported Mussolini, and Hitler.
Among the more well known individual supporters of the Nazis were Andrew Mellon (Secretary of the US Treasury), William Randolph Hearst, Joseph Kennedy (JFK's father), John Rockefeller, Allen Dulles (later head of the CIA), Charles Lindbergh and Prescott Bush (George Bush's father; Dubya's grandfather). Additionally, there were also major companies who wanted to keep supplying and supporting the Nazis because of the huge money they could make. Companies such as General Motors, Ford, Winthrop Chemical, Exxon (then called Standard Oil), ITT, Alcoa, Dow Chemical, General Electric, National City Bank and DuPont were all keen to continue making profits from Hitler's regime.
Suggesting that
"America was late joining the war" might be true, but it doesn't paint a true and accurate picture of what its President and the majority of its people thought. The facts are that in the two years prior to Pearl Harbour, many thousands of Americans went to Europe to join the fight against Nazism by joining the RAF, the Royal Navy and the British Army. Those who wanted America to stay out of it were a small but noisy and influential minority.
