What if, following the election of Lincoln, Buchanan dropped dead and Breckenridge was US President during the winter of secession?
I think he'd be likely to recognize the secession of the 7 states plus Arizona, as well as withdraw troops from the south and hand over Federal Assets.
With no troops at Fort Sumter, there'll likely be a different cause of the start of the war but I imagine the war starts in April 1961 nonetheless.
When Lincoln becomes President in March, Breckinridge hightails it out of the union.