Missouri's Jacksonian Democrats, led by Senator Thomas Hart Benton, engaged in a number of debates, during the 1830 Congressional election season, that saw many fiery speeches, on issues of banking, currency stability, and western land use.

During one of those speeches, Congressman Spencer Darwin Pettis, a Benton acolyte, harshly criticized Biddle's brother Nicholas, President of the Second Bank of the United States.

Things escalated dramatically on July 9, 1831, when Biddle heard that an ill Pettis was resting in a St. Louis hotel.

[5] After sufficient time to recover from the beating, on August 21, 1831, Congressman Pettis challenged Biddle to a duel, which was promptly accepted.

In short, it was suicidal and seen as a ploy by some observers and later historians to make Pettis back down and thus lose the affair of honor without bloodshed.

[6] At five p.m. on August 27, 1831, Biddle and Pettis, along with their seconds, Major Benjamin O'Fallon and Captain Martin Thomas, respectively, met on Bloody Island, a small sandbar located in the Mississippi River between St. Louis and the Illinois shore.

As large crowds watched from the St. Louis riverfront, Biddle and Pettis obeyed the commands to step, turn, and fire.

As a war hero, Thomas Biddle was buried with full military rites at Jefferson Barracks in St. Louis.