commenced practice in Sumner County. He ran unsuccessfully for Congress in 1827 and 1829, and served on Gallatin's Board of Aldermen from 1831 to 1835. He was elected to the Tennessee Senate in 1835, and served until the following year. At the outbreak of the Second Seminole War in 1836, Trousdale formed his own company, and was elected colonel of the Second Regiment, First Brigade. His regiment took part in several skirmishes, and helped defeat Seminole forces at the Battle of Wahoo Swamp in November 1836. In 1837, Trousdale once again ran for Congress for the 6th District congressional seat, but lost to William B. Campbell, his former subordinate in the Seminole War and his future gubernatorial opponent. He ran again in 1839 and 1845, but being a Democrat in a primarily Whig district, he was never successful. Trousdale campaigned for the unsuccessful Democratic presidential candidate, Martin Van Buren, in 1840. During the Mexican–American War, Trousdale joined the Army with the rank of Colonel, and commanded the 14th U.S. Infantry. This regiment landed at Veracruz on June 13, 1847, and was placed under General Gideon Pillow's 3rd Division. Trousdale's forces linked up with Winfield Scott's forces on July 8, and began the march inland to Mexico City. Trousdale took part in the Battle of Contreras and the Battle of Churubusco on August 20, and was grazed in the shoulder while fighting in the Battle of Molino del Rey on September 8. Trousdale commanded two regiments (the 14th and 11th) and an artillery battery at the Battle of Chapultepec on September 13. During this battle, his right arm was shattered by enemy fire, though he continued fighting, and managed to lead a charge that captured an enemy cannon. For his actions at Chapultepec, Trousdale was brevetted to brigadier general by President James K. Polk on August 23, 1848. Governor and later political endeavors In 1849, Trousdale received the Democratic nomination for governor. His Whig opponent, Neill S. Brown, had been opposed to the Mexican–American War, and was struggling with divisions over the issue of slavery in the national Whig Party. Trousdale, on the other hand, was riding a wave of popularity for his service in the war. As a result, Trousdale edged Brown by 1,400 votes in the general election. In Trousdale's reelection campaign in 1851, his opponent was William B. Campbell, a fellow Mexican–American War hero who had served under