How did cotton production contribute to divisions in the United States leading up to the Civil War?

Slave labor was needed to make cotton profitable, and slavery was a divisive issue at the time.

The majority of the nation's income was from cotton production, and the South wanted a greater share of the economic benefit.

Cotton imports were banned in Europe because of slavery, and the North especially needed that income.

The cotton crop could not be processed in the South, and the North wanted a greater share of the economic benefit for processing it.