Classic Millard Fillmore Compromise
On this day in 1850, Millard Fillmore took the oath of office after Zachary Taylor died of cholera.
If the Civil War could have been prevented, the death of Zachary Taylor made it inevitable. Taylor, one of the largest slave holders in the country at that time, refused to allow slavery to extend into the western territories, shocking many of those who voted for him thinking he supported their interests. He refused to sign the Compromise of 1850 and threatened to personally hang any governor who advocated secession. And he was enough of a national hero to get away with it.
Millard Fillmore, on the other hand, was about as milquetoast as you could get (until the election of James Buchanan) and signed the Compromise of 1850, thinking that it would settle the issue of slavery once and for all.