On September 9, 1980, eight Catholic activists including Daniel and Philip Berrigan entered the General Electric plant at King of Prussia, Pennsylvania, hammered on Mark 12A missile nose cones, and poured their own blood on documents — the first Plowshares action, taking Isaiah's injunction to beat swords into plowshares literally. Convicted of burglary and criminal mischief and sentenced to up to ten years, the Plowshares Eight spent a decade in appeals before being resentenced in 1990 to time served; by then the action had seeded a movement.
Through the Reagan buildup, dozens of Plowshares groups hammered on bombers, submarines, and missile silos and accepted the consequences in court, where judges routinely barred any defense of necessity or international law. Sentences escalated sharply for silo actions in the Midwest: Helen Woodson and Fr. Carl Kabat drew eighteen-year terms for the 1984 Silo Pruning Hooks action — punishment for symbolic disarmament that exceeded many sentences for violent crime, and that made the Plowshares prisoners a fixture of the era's political-prisoner rolls.