Why would Americans in free states want the slave states to remain part of the United States, as opposed to just letting them leave the Union? > Most Northerners recognized the South as part of the United States and felt that the South was crucial to the country's economy.
> Most Northerners supported a very strong federal government and believed that only government control could end slavery.
> Most Northerners believed the only way to change the slave-holding states was to keep them in the Union and work for change through legislative means.
> Most Northerners wanted the slave states to remain in the Union so that the Underground Railroad would continue to bring cheap labor to the North.