A young university student and member of the Italian Communist Party (PCI), he replaced Placido Rizzotto—murdered by the mafia—as leader of the peasant movement for land rights. A few years later, Pio took a stand against the Sack of Palermo and joined the mobilization against the missile base in Comiso. He fought against the mafia, for legality, justice, and peace.

His presence on the Parliamentary Antimafia Commission was crucial. Alongside judge Cesare Terranova and others, he co-authored the minority report—one of the cornerstones of the fight against organized crime.

From that parliamentary experience came his revolutionary legislative proposal, the first to define the crime of mafia-type association and to allow for the confiscation of assets from those convicted. The Italian Parliament passed the law after his assassination—carried out in Palermo on April 30, 1982 (alongside his party comrade Rosario Di Salvo)—naming it the Rognoni-La Torre Law.