What sparked ww2 and why was the US involved in it

World War Two was sparked by the attack on the Pearl Harbor in Hawaii. Japan was mad because they didn't get their "new deal", they also walked out on the nations meeting where all the nations come together to meet. So the US said they weren't allowed to trade with them. Then they also had a lack of oil supply. So they got mad and attacked the Pearl Harbor. Then that was the spark that lead the US WW11. The US also had to worry about Germany and Hitler taking over the world with war!

World war 2 involved the US and because they were stronger so they had to go to war with their alliances