I belive it was the Battle of Midway in June 1942.
Short answer: The Industrial Revolution
It basically said everything regarding the Senators in the Senate, such as the requirements of a Senator, how long one term is for them is, that each state got 2 Senators, etc.
Um im guessing this is multiple choice about who feared the oppression of the enslaved people? But it would be the Americans did not want it to happen mostly in the south