Thomas Hart Benton's declaration of oppositon to slavery led to a split of Democrats in Missouri into Pro-Benton and Anti-Benton camps for several elections.
Congressmen elected as Benton Democrats include John S. Phelps, Thomas Hart Benton, and Francis Blair.
Phelps went on to serve as a Democrat and an Anti-Benton Democrat. Benton served one term before losing in 1854. Blair was elected as a Benton Democrat in 1856, and was a Republican by 1858.