Slavery becomes "expansionist". What motivated white southerners to modify their view about slavery? ​

Northerners held mixed views on slavery. Some, called abolitionists, opposed slavery and its expansion. Others only sought to limit slavery to the South. Some workers in the North, who feared that freed slaves might move north to claim their jobs, also supported the continuation of slavery. Many northern business leaders also favored slavery because they profited from it. Many white southerners supported not only the continuation but also the expansion of slavery. The southern economy and way of life largely depended on enslaved labor.