 He presided over the convention, which passed resolutions regarding states rights and reaffirming the institution of slavery.The following year, with the outbreak of the Civil War and Texas's secession, Sexton briefly joined the Confederate States Army, but resigned after being elected to fill a vacancy in the State Senate.In 1862, he was elected to the First Confederate Congress as a representative from Texas's 4th District and left home in July to travel to Richmond, Virginia, to assume his duties, arriving in mid-August.