The causes of secession were complex and have been controversial since the war began,
but most academic scholars identify slavery as the central cause of the war. The issue has been further complicated by
historical revisionists, who have tried to offer a variety of reasons for the war.
[16] Slavery was the central source of escalating political tension in the
1850s. The
Republican Party was determined to prevent any spread of slavery to the territories, which, after they were admitted as states, would give the North greater representation in Congress and the Electoral College. Many Southern leaders had threatened secession if the Republican candidate, Lincoln, won the
1860 election. After Lincoln won, many Southern leaders felt that disunion was their only option, fearing that the loss of representation would hamper their ability to promote pro-slavery acts and policies.
[17][18] In his
second inaugural address, Lincoln said that "slaves constituted a peculiar and powerful interest. All knew that this interest was, somehow, the cause of the war. To strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the Union, even by war; while the government claimed no right to do more than to restrict the territorial enlargement of it."
[19]
