This was a popular thing when I was young, and yes there was a debate over what state laws/federal laws wanted, but Kansas has a very interesting history - were runaway slaves left Missouri and headed into Lawrence and people of Missouri took the law into their own hands to hunt down fugitive- runaway slaves, sometimes because they just wanted the bounty or the reward.

In one incident, the sheriff from a city in Missouri was shot at and as a response people from Missouri Road into Lawrence and burnt down most of the big buildings and killed a couple of people and stole several horses. This was known as the border war and it occurred far before 1861. It was all about racism, hatred, and money, and it had absolutely nothing to do with state rights 

Yep, it was about the north fighting for their right not NOT participate in slavery, as the south tried to force slavery upon them (fugitive slave act), then seceded from the US and attacked it.

It was the war of southern aggression.

I'm pretty sure the flag was the least of the problems here.