History of Congress and the Capitol

Tensions ran high over the question of slavery in the Western territories when Senator Charles Sumner rose to speak in 1856. The Massachusetts abolitionist let loose a fiery speech, denouncing expansion of slavery into Kansas. He attacked pro-slavery opponents by name—including Senator Andrew Butler of South Carolina.

Several days later, on May 22, Representative Preston Brooks, a relative of Butler’s, found Sumner sitting at his Senate desk. Raising his gold-headed walking stick, Brooks struck the Massachusetts senator repeatedly. Badly wounded, Sumner was unable to return to the Senate full-time for three years. His empty desk stood as a powerful symbol of the increasing North–South antagonism, an omen of the looming Civil War. Brooks resigned his House seat but was immediately reelected— then died shortly after.

"Sir, to assail a member of the Senate ... 'for words spoken in debate,' is a grave offense."
—Senator Henry Wilson of Massachusetts, May 23, 1856

Rarely has a presidential election brought such immediate consequences. Abraham Lincoln’s victory in 1860 triggered the secession of America’s Southern states even before the new president took office in March of 1861. On January 21, senators from Alabama, Florida, and Mississippi rose to bid their Senate colleagues farewell. The last to speak was Jefferson Davis of Mississippi. In an emotional address before a hushed Senate, Davis defended secession, insisting that Mississippians were only exercising their rights.

Within weeks, Fort Sumter fell to the Confederacy. Union soldiers, sent to protect Washington, camped out in the Senate Chamber while the Senate was adjourned. In a flash of anger, one soldier tried unsuccessfully to demolish the desk that had once been assigned to Davis. Americans of all regions recognized clearly that the nation stood at a dangerous crossroads.

The Constitution requires all government office-holders to take an oath to support that document, but it establishes a specific oath only for the president. In 1789, Congress drafted a simple 14-word pledge. No one felt anything more was needed—until the Civil War.

In 1862, Congress adopted the "Ironclad Test Oath." Civil servants and military officers had to swear loyalty to the Union and affirm no previous disloyalty—a clause aimed at Confederate sympathizers. Senators didn’t have to take the oath, but many did.

Angered by those who refused, Massachusetts Senator Charles Sumner promoted an 1864 Senate rule making the new oath mandatory. Four years later, to encourage reunification, Congress created an alternative pledge for Southerners. Finally, in 1884, lawmakers replaced the wartime oath with the one used today.

"I , _________, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take This obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter: So help me God."
— Oath of office, version instituted in 1884 and still in use today

The bullet that felled Abraham Lincoln in 1865 made Andrew Johnson president. The new chief executive backed a plan for quickly reintegrating the former Confederate states into the Union. Congress’s more radical Republicans demanded stronger measures to punish rebellious states and protect the rights of freed slaves. The dispute boiled over when Johnson prepared to dismiss a cabinet member who had strong congressional support.

Overriding Johnson’s veto, Congress passed legislation denying the president’s power to remove officials without Senate consent. Johnson ignored the act, provoking impeachment by the House and a Senate trial. On May 16, 1868, seven Republican senators defied party leaders, voting with the 12 Democrats to acquit Johnson of “high crimes and misdemeanors”—by a one-vote margin. Ironically, Johnson returned to Washington in 1875 as a senator, the first former president to serve in the chamber.