Retaliation for US military actions in Grenada and Lebanon
Members of the Resistance Conspiracy were later charged. A warning had been called through before the bomb detonated, and the explosion did not injure anyone. The bombing marked the beginning of tightened security measures throughout the Capitol. A previous protest in the Capitol, in March 1971 also exploded a bomb. Again people were warned beforehand and no-one was hurt. This protest was at the ongoing US-supported bombing of Laos. A group called Weather Underground, a radical faction of the Students for a Democratic Society (SDS), claimed responsibility. Weathermen bombings also targeted the Pentagon, and the State Department. No one was killed in these bombings either, because the bombers always called in an advanced warning.