They tried to pass a lot of laws trying to bring the slaves back. That was IMPOSING laws on other states. You are right.
You have to remember that a slave was property. What the South was furious about was if they took a slave with them to a northern state that slave could be taken away from them. It was the same to them as if someone were to take your wagon from you or take anything else from you without repayment.
The North on the other hand, moving away from slavery, didn't see them as property any longer and therefore felt they had every right to free them if brought into their territory. Hence.. the tension grew until actions too place that triggered the civil war. It wasn't that the southern states objected to the northern states' decisions to no longer support slavery.
It was a combination of the above with the north states attempting to confiscate the "property" of southerns who cross into northern states along with the north's pursuit of completely disallowing slavery in any future states/colonies. Otherwise, the south in general was okay with each individual northern state deciding to no longer allow slavery. Slavery was of course wrong, but mindsets were different back then so I wouldn't be too quick to criticize the intent of the South's secession.
It was basically a major turning point where neither side could really afford to give in to compromise.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.