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(born about 1793, died 1871), a Louisiana lawyer, and Congressman from that State in 1843-45. He was sent as U.S. Minister to Mexico in 1845, but was not received. From 1853 to 1861 he was a prominent member of the U.S. Senate, on the State-rights side. Having joined the Confederacy, Slidell was despatched as commissioner to France. With the other Confederate commissioner, Mason, he was seized en route by the American naval commander, Wilkes. (See Trent Affair.) Having been released, he continued his voyage to France, but did not induce the Government to side openly with the South. He settled in England after the war.