What was the purpose of the US congressional compromises leading up to the US Civil War?

Compromises between the North and the South began with the writing of the US Constitution, however, in the 19th century, three major compromises were made between the North and the South. The purpose of the compromises were to keep the number of free states and slave states equal in number. The last compromise can be said to be the Kansas-Nebraska Act of 1854. There citizens would vote on slavery in there own territories. The US Congress, thereby washed its hands of the old style compromises. The people within territories would vote on the issue, Congress retreated from the slavery issue battle.