The surprise attack cost many American lives and did extensive damage to the United States Pacific Fleet. The most important consequence of the attack was the declaration of war by the United States on Japan.
This declaration was requested by President Roosevelt before a joint session of Congress on December 8, 1941.
It was the biggest political blunder of his career. From that point, he began to devote his money & energies in the support of his sons.
JFK also joined the Navy & served in the PT boat squadron in the South Pacific. He was captain of the PT109. The 109 was struck by a Japanese destroyer off the Solomon Islands resulting in the deaths of two of the crew. JFK, although injured, was able to lead his crew to be rescued. He won the Purple Heart & Navy & Marine Corps Medals for his heroism.