On May 22, 1856, the "world's greatest deliberative body" became a combat zone. In one of the most dramatic and deeply ominous moments in the Senate's entire history, a member of the House of Representatives entered the Senate chamber and savagely beat a senator into unconsciousness.

The inspiration for this clash came three days earlier when Senator Charles Sumner, a Massachusetts antislavery Republican, addressed the Senate on the explosive issue of whether Kansas should be admitted to the Union as a slave state or a free state. In his "Crime Against Kansas" speech, Sumner identified two Democratic senators as the principal culprits in this crime—Stephen Douglas of Illinois and Andrew Butler of South Carolina. He characterized Douglas to his face as a "noise-some, squat, and nameless animal . . . not a proper model for an American senator." Andrew Butler, who was not present, received more elaborate treatment. Mocking the South Carolina senator's stance as a man of chivalry, the Massachusetts senator charged him with taking "a mistress . . . who, though ugly to others, is always lovely to him; though polluted in the sight of the world, is chaste in his sight—I mean," added Sumner, "the harlot, Slavery."

Representative Preston Brooks was Butler's South Carolina kinsman. If he had believed Sumner to be a gentleman, he might have challenged him to a duel. Instead, he chose a light cane of the type used to discipline unruly dogs. Shortly after the Senate had adjourned for the day, Brooks entered the old chamber, where he found Sumner busily attaching his postal frank to copies of his "Crime Against Kansas" speech.

Moving quickly, Brooks slammed his metal-topped cane onto the unsuspecting Sumner's head. As Brooks struck again and again, Sumner rose and lurched blindly about the chamber, futilely attempting to protect himself. After a very long minute, it ended.

Bleeding profusely, Sumner was carried away. Brooks walked calmly out of the chamber without being detained by the stunned onlookers. Overnight, both men became heroes in their respective regions.

Surviving a House censure resolution, Brooks resigned, was immediately reelected, and soon thereafter died at age 37. Sumner recovered slowly and returned to the Senate, where he remained for another 18 years. The nation, suffering from the breakdown of reasoned discourse that this event symbolized, tumbled onward toward the catastrophe of civil war.