David Rice Atchison was born in Lexington, Kentucky, in 1807 and attended Transylvania University, where five classmates, including Jefferson Davis, later served in the Senate. In 1830 he moved to Liberty, Missouri, opened a law practice, bought a plantation and became a slaveholder, partnering with Alexander William Doniphan. He defended Joseph Smith in land disputes, entered the Missouri House in 1834, secured the Platte Purchase in 1837 and became a major general in the 1838 Mormon War. Appointed to the Senate at 36, the youngest senator from Missouri at the time, he was elected president pro tempore by December 1845.

On Sunday, March 4, 1849, Zachary Taylor delayed his oath to Monday, and allies later claimed Atchison was president for that day, though his own Senate term had also ended and he never took an oath. In the Senate he demanded repeal of the Missouri Compromise as the price for organizing Kansas and Nebraska, leading Stephen Douglas to introduce the Kansas-Nebraska Act in 1854. On March 30, 1855, he led about 5,000 armed Missourians across the border to seize polling places and install a pro-slavery legislature, which President Franklin Pierce accepted while firing the territorial governor. In the Civil War he served in the Missouri State Guard under Sterling Price, won at Liberty in 1861, resigned after Pea Ridge and went to Texas.

• His tombstone in Plattsburg, Missouri, reads “President of the United States for one day.”
• He later joked that he slept through his presidency and fired no one during his administration.
• Charles Sumner’s Crime Against Kansas speech of May 1856 compared him to the Roman conspirator Catiline.
• Days later he urged hired Texans under a red flag to move on Lawrence, Kansas, and destroy anti-slavery printing presses.
• A fire at his cottage before his death in 1886 destroyed his library of letters and records.