Excellent question which no one ever asks. President Bell, President Breckinridge or President Douglas? In any case, there would have been a tremendous outcry from the Republicans, who had rapidly become popular and carried many of the Congressional and State races in the late 1850s. Would there have been a secession of Northern states?

Your response on the "Fire-Eaters" is right on target. Using inflamitory (no pun intended) issues that arose in 1858-59, they finally succeeded in making secession a viable option. Sesessionists were always a small minority prior to that time -few listened to them. How they finally managed make secession a viable option is something I can't really explain.