“As many have noted, the January 6th storming of the U.S. Capitol by a violent right-wing mob was the first successful seizure of the structure since it was taken by the British in 1814. However, it was not the first time that domestic extremists had targeted the capitol building. In 1954, armed Puerto Rican nationalists wounded five members of Congress in a shooting spree. In 1971, the radical left Weather Underground detonated a bomb in a north wing restroom that caused minor damage. Most recently, in 1983, a Marxist-Leninist terrorist group exploded a bomb that caused extensive damage to the Senate side of the building. This incident, though now largely forgotten, was arguably the most destructive domestic terror attack on the U.S. Capitol prior to January 6.

On the night of November 7, 1983, just moments after a phone warning was received, a bomb detonated on the second floor of the north (Senate) wing of the capitol. An article on the Senate history website describes the damage:

The force of the device, hidden under a bench at the eastern end of the corridor outside the chamber, blew off the door to the office of Democratic Leader Robert C. Byrd. The blast also punched a potentially lethal hole in a wall partition sending a shower of pulverized brick, plaster, and glass into the Republican cloakroom. Although the explosion caused no structural damage to the Capitol, it shattered mirrors, chandeliers, and furniture. Officials calculated damages of $250,000. (Bomb Explodes in Capitol)

There were no casualties. The bombing was claimed by the “Armed Resistance Unit,” as a response to recent American military interventions in Grenada and Lebanon. The name “Armed Resistance Unit,” investigation would reveal, was a cover adopted by a group whose real name was the May 19th Communist Organization. [Via the official blog of the Cold War & Internal Security Collection, which is part of the Federal Documents Collection at J.Y. Joyner Library, East Carolina University. Click here for more about the purpose and contents of this site.]