SLIDELL, JOHN (1793-1871), American diplomatist, was born in New York in 1793. He graduated from Columbia college in 1810, studied law, and practised at New Orleans, La., where he settled in 1825. He belonged to the House of Representatives as a state's rights Democrat from 1843 to 1845, when he resigned and was sent by President Polk on a secret mission to Mexico, with power to adjust the difficulties growing out of the annexation of Texas to the United States, and to acquire by purchase both New Mexico (including the present Arizona) and Upper California. He was not, however, received by the Mexican government. From 1853 to 1861 he represented Louisiana in the Senate. He is sup posed to have assisted Buchanan's nomination for the presidency in 1856. When Louisiana seceded in 1861, Slidell withdrew from the Senate, and late in 1861 was sent by the Confederate Govern ment as commissioner to France. With James M. Mason (q.v.),
the Confederate commissioner to England, he was taken from the British steamer "Trent" by Captain Charles Wilkes of the United States navy, and was imprisoned at Fort Warren in Boston har bour. In Jan., 1862, at the demand of England, the Confederate commissioners were released, and Slidell proceeded to France. His mission there was to secure the recognition of the Confederate States; in this he was unsuccessful, but he was able to secure sup plies for the Confederate army and navy. After the war he settled in England, and his daughter married a French nobleman. He died in London on July 29, 1871.
See Samuel Abbott Green, James Murray Mason and John Slidell in Fort Warren, Boston Harbor (1912) ; Louis Martin Sears, "A Con federate Diplomat at the Court of Napoleon III.," in American His torical Review, vol. xxvi. p. 255-281 (1921) and Louis Martin Sears, John Slidell (1925).