If you are not going to bother knowing America's history, then why are you parading your inaccurate assumptions? Slavery was always a major issue in this country. Dating all the way back to the Virginia compromise of the constitution. If the north wasn't upset as you imply, then slavery would not have been outlawed in numerous states in the later half of the eighteenth century and early nineteenth. So... Who doesn't know U.S. history again?
Do you want to go into the whole free-state slave-state balancing act that was being played with statehood?