Final answer:
The attack on Pearl Harbor was a shocking event that led to a united response from Congress, resulting in a declaration of war against Japan. President Roosevelt's message to Congress seeking a declaration of war was largely unaltered due to the gravity of the situation.
Step-by-step explanation:
The reason there were so few alterations of President Roosevelt’s message to Congress asking for a declaration of war against Japan is because the attack on Pearl Harbor by Japan on December 7, 1941 was a surprise and devastating event that severely impacted the nation. The attack killed hundreds and shocked the country, leading to a united response from Congress. President Roosevelt gave a speech addressing the attack and requested a declaration of war, which was approved by Congress with only one dissenting vote.