April 17, 1850: during a heated debate on the Senate floor, Senator Foote pulls a gun and threatens to shoot Senator Benton. Senator Dickinson tries to wrestle the gun away and [POD] during their struggle, Foote accidentally shoots and kills V.P. Millard Fillmore, who was standing a few feet away. Zachary Taylor still gets sick and dies that summer, resulting in David Rice Atchison as Acting President.
Under the Succession Act of 1792 there must be a special election in November 1850. It's a corrupt, chaotic shitshow, with both Atchison and Seward claiming they won, and refusing to concede to the other.