Right. I stand corrected. There was a fourth candidate in 1860, however, in addition to Lincoln, Vice President Breckenridge, and Senator Douglas: John Bell of the Constitutional union Party.
Fillmore’s American Party was a remnant of the Whigs, and I think Bell’s party was also a Whig remnant.
Bell’s Constitutional Union Party was a Whig remnant with the main goal of preserving the Union. In addition to former Southern Whigs it attracted Southern Democrats who opposed secession.
Democrats split along Northern and Southern lines with two candidates running, Douglas and Breckinridge.
And then there was the Republican Party.
When Millard Fillmore ran on the American Party ticket in the previous election in 1856 he did it because he predicted that if the Republican Party with their open hostility to the South won the Presidency that it would bring civil war. A prophet for sure.