ABSTRACT
Although Polk lacked charisma, a sense of humor, and broad popularity, he was an efficient chief executive. But to preserve party unity, he had pledged not to run for a second term. (A hard-driven, furious worker throughout his presidency, Polk died just three months after leaving office.) The Democrats turned to the bland Senator Lewis Cass of Michigan. Cass had previously served as territorial governor of Michigan and was the first Democratic nominee from the Northwest. He had also been a foremost proponent of popular sovereignty, which held that the people of a territory, expressing their will through their territorial legislature, would decide whether the territory should permit slavery. General William Butler of Kentucky, a veteran of the War of 1812, was selected as Cass's running mate.
