US Senator, US President. He served as President of the United States for one day, and his grave marker proclaims this honor. He was twice elected as a Democrat Senator from Missouri to the United States Senate, serving first from 1843 to 1848, then from 1849 to 1855. He served as President Pro Tempore of the Senate for six years, which put him in the position of possibly serving as the United States President. When the term of President James Polk ended on Sunday, March 4, 1849, President-Elect Zachary Taylor refused to take the oath of office on a Sunday for religious reasons. At that point, Senator Atchison is said to have been President of the United States for one day. In reality, Zachary Taylor's term began on March 4th, despite his not having taken the oath. According to the Constitution, Taylor's term began on March 4th, regardless of whether he had taken the oath. Not taking the presidency seriously, David Atchison spent the entire day that he was alleged to have been President in bed. "I never for a moment acted as President of the U.S.," he declared in an 1880 letter. Atchison did not sign any official documents, and Congress did not decide who was President on March 4th. After attending Transylvania University in Lexington, he studied law and was admitted to the Kentucky bar in 1829 before migrating to Missouri the next year to start a practice. He supported slavery and used the enslaved to work his plantation. He began his political career by being elected to the Missouri House of Representatives in 1834. With the death of Senator Lewis Linn, he was appointed to the US Senate in 1843, followed by his being elected for his own term. Atchison served as a major general in the Missouri State Militia in 1838 during Missouri's Mormon War and as a Confederate brigadier general during the American Civil War under Major General Sterling Price in the Missouri Home Guard. He saw action at the Battle of Mills Landing. Counties and townships in Missouri and Kansas are named in his honor. In 1991, he was inducted into the Hall of Famous Missourians, and a bronze bust depicting him is on permanent display in the rotunda of the Missouri State Capitol. There is a full statue of him in front of the Clinton County Courthouse, Plattsburg, Missouri. The Atchison County Historical Museum has been nicknamed the "Smallest Presidential Library." He never married.