Japan had a quest for more power and natural resources. To obtain these, they started invading and taking over other countries of interest. They invaded eastern China and had some it under their control. They used their huge army to help them conquer.
The Hope Within the Hopeless
The U.S saw that Japan was gaining a lot of power through conquering other countries, so they decide to stop giving them oil and steel. They thought that this could help to weaken their invasions and weapons.
FDR "A Date which will live in infamy"
The Japanese were angry that we had cut off their oil supplies, and they realized that our military and navy were one of their biggest threats. So, they decided to attack our naval base at Pearl harbor, Hawaii. They destroyed our battleships and many lives were lost.
Although the entire battleship fleet was destroyed, the aircrafts were out at sea, away from the bombs. At this time, the aircrafts were better advanced than the battleships, so we still had our more important weapon intact.
On December 8, 1941, President Franklin Roosevelt said a speech about the attack on Pearl Harbor. He was trying to convince the Congress that we should fight back against the Japanese. He described the attack as a, "date which will live in infamy."
Even though the Japanese completely destroyed our battleships, we still had a navy to fight with. Our aircrafts survived, and we were able to rebuild almost all of our battleships relatively quickly. They might have destroyed out battleships, but we never backed down, we only came back stronger.