Extreme class difference is the one I would choose
Answer:
We should remember the Pearl Harbor soldiers because if it weren't for them, we would be speaking German today. Essentially, the Nazis would have taken over us, and we'd be speaking another language. So, the US joining the Allies after the 12/7/1941 attack was an important event in WWII.
I think it is the three-fifths compromise.
How about "How were Native Americans treated throughout the history of the United States?"