Why would Lincoln's election trigger a war between the states?

Lincoln's election in 1860 triggered a war between the states primarily because he was seen as a threat to the institution of slavery, which was integral to the Southern economy and way of life. His platform of halting the expansion of slavery into new territories alarmed Southern leaders, prompting fears of losing political power and ultimately, their way of life. This led to the secession of several Southern states from the Union, which perceived their interests as being irreconcilably opposed to those of a Lincoln-led government, ultimately culminating in the Civil War.