The Missouri issue was the main issue they focused on. The rapidly growing North controlled the House of Representatives. Southerners thought it was essential to preserve a balance in the Senate. The Northerners said that Missouri extended hundreds of miles north of the Ohio River, which was at that time considered to be the natural division of slavery. The debate was about political influence, rather than if slavery was right or wrong. Northerners objected to adding new slave states because under the 3-5ths Compromise these states would be overrepresented in Congress. Angry debate lasted for months in