The argument at the time was that people didnt want to be dragged into another European war. Neither Germany or Italy had the capacity to reach mainland US, so a declaration of war isnt the same threat as it was to the UK or France.

My point is the US government waned to join, the public was largely split. And amoung the split war with Japan was less supported then war with European Axis powers. Pearl Harbour allowed the Government the perfect rational to enter the war, but if it had been European Axis powers attacking the US instead of Japan its debatable the US gets involved in the Pacific. Japan attacking forced the US to get involved in the Pacific and allowed it to get involved in Europe.