In 1834, King was elected to the first of two terms in the
Missouri House of Representatives. During his time on the bench he presided over the trial of
Joseph Smith, founder of the
Latter Day Saint movement, during the
1838 Mormon War. Smith and sixty of his followers were brought before King in a
Richmond, Missouri, courtroom following their surrender after the
Battle of Far West in
Caldwell County. However, Smith and the rest were ordered held in the
Liberty Jail in
Clay County, Missouri. Smith was later allowed to escape custody by his captors and fled Missouri for Illinois. King remained active in Democratic politics during his time as a judge, being a strong supporter of
Martin Van Buren in the 1840 presidential campaign. King was a contender for the Democratic Party's nomination for Missouri Governor in 1844, but lost out narrowly to
John Cummins Edwards. King presided over a time of great growth in Missouri. In his first year in office alone 142 new companies were granted state charters. Although fiscally conservative, King saw the benefits of expanded rail service and thus in 1850 recommended that $3.5 million (~$ in ) in state bonds be issued to fund two rail projects. King returned full-time to his law practice as well as keeping a hand in politics. In July 1855, King was a delegate to the Missouri Slave Owners Convention. Over 200 delegates gathered in
Lexington, Missouri, to create a series of resolutions that advocated the position of states' rights held by so many other slave-holding southern states and to also endorse a pro-slavery position for the
Kansas Territory. However, King later expressed his opposition to the Kansas
Lecompton Constitution and Missourians crossing the border to vote on it. King served as the
Missouri 6th Congressional District Representative from March 4, 1863, to March 3, 1865. Among the important legislation during his term was the
Coinage Act of 1864, establishment of the
Freedmen's Bureau, and passage of the
Thirteenth Amendment to the United States Constitution. King very much wanted to be reelected for a second term in 1864; however, he was soundly defeated, coming in a distant third to Republican
Robert T. Van Horn and fellow Democrat
Elijah Hise Norton. After his election loss, King returned to Missouri and continued his law practice for the few remaining years of his life. King died on April 22, 1870, in
St. Louis, Missouri. He was buried in the city cemetery in
Richmond,
Ray County, Missouri. ==Family==