The biggest impact of the civil war was the end of slavery.
Explanation:
The southern states had been a little aloof from the US for a long time.
This was partially because f the 'peculiar practice' and many other such things.
These were solved by might and the southern states, albeit with some resentment were brought back into the fold of the union.
At the same time, the south had to give away slavery and then the freed men also became citizens and started having an influence on the policies, albeit a minuscule one.
The oldest known peace treaty was the Egyptian-Hittite peace treaty. It is also known as Eternal treaty or Silver treaty. The treaty was signed between Hittite empire and Egypt in 1258 BC after the long war, which continued for over 2 centuries. After the Battle of Kadesh in 1274 BC, the sides sought a peace treaty because of heavy casualties on both sides. And it was ratified 16 years later that battle.
The northerners were angry in response to the Fugitive Slave Act, which eventually drove both sides even further apart and resenting each other more.
