A bomb explodes in the Capitol building in Washington, D.C., causing an estimated $300,000 in damage but hurting no one. A group calling itself the Weather Underground claimed credit for the bombing, which was done in protest of the ongoing U.S.-supported Laos invasion.

The so-called Weathermen were a radical faction of the Students for a Democratic Society (SDS); the Weathermen advocated violent means to transform American society. The philosophical foundations of the Weathermen were Marxist in nature; they believed that militant struggle was the key to striking out against the state to build a revolutionary consciousness among the young, particularly the white working class. Their primary tools to achieving these ends were arson and bombing.

Among the other targets of Weathermen bombings were the Long Island Court House, the New York Police Department headquarters, the Pentagon, and the State Department. No one was killed in these bombings, because the bombers always called in an advanced warning. However, three members of the Weather Underground died on March 6, 1970, when the house in which they were constructing the bombs exploded.