Commissioner John Slidell
John Slidell served as agent to Mexico in the months preceding the outbreak of war between that nation and the United States. A native of New York City, Slidell had gone south after the War of 1812 and rose to become a scrappy New Orleans politician. He entered the U.S. Congress in 1842, and became a close ally of James K. Polk.
Slidellís connections landed him the official task of negotiating a deal with Mexico. He was instructed to offer a settlement of all U.S. claims against Mexico, in exchange for recognition of the Rio Grande as the boundary between the two nations. In addition, Polk instructed Slidell to try and buy California for $25 million.
The Mexicans rejected Slidell and his mission outright. He responded to President Polk by hinting that the Mexican reluctance to negotiate might require a show of military force by the United States. Based on this intelligence, Polk ordered General Zachary Taylor to head for the Rio Grande. Slidell remained in Mexico until March 1846, but left as war became unavoidable.
After the U.S.-Mexican War, Slidell rose to prominence in Louisiana politics. When that state seceded from the Union in 1861 and joined the Southern Confederacy, Slidell served as minister to France. He remained in Europe until his death in 1871.