John Slidell John Slidell ( 1793July 9 , 1871 ) was an American politician , lawyer and businessman . A native of New York , Slidell moved to Louisiana as a young man and became a staunch defender of southern rights as a U . S . Representative and Senator . He was the older brother of Alexander Slidell Mackenzie , a US naval officer . Early life . He was born to the merchant John Slidell and the former Margery Mackenzie , a Scot . He graduated from Columbia University ( then College ) in 1810 . In 1835 , Slidell married the former Mathilde Deslonde , and they had three children , Alfred Slidell , Marie Rosine ( later " comtesse " [ Countess ] de St . Roman ) , and Marguerite Mathilde ( later " baronne " [ Baroness ] Frederic Emile d ' Erlanger ) . Merchant , lawyer , politician . Slidell was in the mercantile business in New York before he relocated to New Orleans . He practiced law in New Orleans from 1819 - 1843 . He was the district attorney in New Orleans from 1829 - 1833 . He also served in the state ' s House of Representatives . Though he lost an election to the United States House in 1828 , he was elected in 1842 and served a term and a half from 1843 – 1845 , as a Democrat . He served as minister plenipotentiary to Mexico from 1845 - 1846 . Prior to the Mexican - American War , Slidell was sent to Mexico , by President James Knox Polk , to negotiate an agreement whereby the Rio Grande would be the southern border of Texas . He also was instructed to offer , among other alternatives , a maximum of $ 25 million for California by Polk and his administration . Slidell hinted to Polk that the Mexican reluctance to negotiate might require a show of military force by the United States . Under the guidance of General Zachary Taylor , U . S . troops were stationed at the U . S . / Mexico border , ready to defend against Mexican attack . The Mexican government rejected Slidell ' s mission . After Mexican forces attacked at Matamoros , the United States declared war on Mexico on May 13 , 1846 . Slidell was elected to the Senate in 1853 and cast his lot with other pro - Southern congressmen to repeal the Missouri Compromise , acquire Cuba , and admit Kansas . In the 1860 campaign Slidell supported Democratic presidential candidate John C . Breckinridge , but remained a pro - Union moderate until Abraham Lincoln ' s election pushed the Southern states into seceding . At the Democratic Convention in Charleston , South Carolina , in April 1860 , Slidell plotted with " Fire - Eaters " such as William Lowndes Yancey of Alabama to stymie the nomination of the popular Northern Democratic Senator Stephen A . Douglas of Illinois . Civil War . With the passage of the Louisiana ordinance of secession , Slidell resigned from the U . S . Senate and headed home . In a dramatic farewell address , he threatened the boycott of all northern manufacturing and predicted the dominance of southern ships on the seas . He argued that foreign countries would prevent the Union from blockading southern ports : he promised however that the Confederate States would never fire the first shot but should the Union do so then " This will be war , . . . and we shall meet it with . . . efficient weapons . " The historian John D . Winters reports that many Confederates " still thought a peaceful solution could be found . Many believed the Yankee incapable of learning to use a gun or of mustering enough courage to fight ; the emergency [ they mistakenly thought ] would soon dissipate . " Slidell soon accepted a diplomatic appointment to represent the Confederacy in France . John Slidell was one of the two CSA diplomats involved in the " Trent " Affair in November 1861 . After having been appointed the Confederate States of America ' s commissioner to France in September , 1861 , he ran the blockade from Charleston , South Carolina , with James Murray Mason of Virginia . They then set sail from Havana on the British mail boat steamer RMS " Trent " , but were intercepted by the U . S . Navy while en route and taken into captivity at Fort Warren in Boston . After the resolution of the " Trent " Affair , the two diplomats set sail for England on January 1 , 1862 . From England Slidell at once went to Paris , where in February 1862 , he paid his first visit to the French minister of foreign affairs . His mission to gain recognition of the Confederate States by France failed , as did his effort to negotiate a commercial agreement , for example that France might get control of Southern cotton if the blockade were broken . In both cases , France refused to move without the cooperation of England . But he did succeed in negotiating a loan of $ 15 , 000 , 000 from French capitalists and in securing the ship “ Stonewall ” for the Confederate government . Later life . Slidell moved to Paris , France , after the Civil War . He died in Cowes , Isle of Wight , England , at age 78 . He is interred in the Saint - Roman family private cemetery near Paris . He , Judah P . Benjamin and A . Dudley Mann were among the high - ranking Confederate officials buried abroad . Family . John Slidell was a brother of Alexander Slidell Mackenzie , a naval officer who commanded the USS " Somers " on which a unique event occurred in 1842 off the coast of Africa during the Blockade of Africa . In that incident , three crewmen were hanged after being convicted of mutiny at sea . Mackenzie reversed the order of his middle and last names to honor a maternal uncle . Another brother , Thomas Slidell , was chief justice of the Louisiana Supreme Court . He was also the brother - in - law of the American naval Commodore Matthew C . Perry , who was married to Slidell ' s sister , Jane . Perry is remembered for opening United States trade with Japan in 1853 . Legacy . The city of Slidell in St . Tammany Parish , Louisiana was named in his honor by his son - in - law Baron Frederick Emile d ' Erlanger ; the village of Slidell , Texas is also named after him .