Graduated in Political Science at the State University of Milan, lecturer in Sociology of Political Phenomena at the IULM University of Milan, professional journalist since 1987, he has collaborated with several newspapers including Il Corriere della Sera, Il Messaggero, La Stampa and La Repubblica, in 2001 he founded the association for the protection of freedoms With good reason, of which he is president. Elected in 1994 and 1996 to the Senate in the ranks of the Greens, of which he was national spokesperson from 1996 to 1999, from 2006 to 2008 he was Undersecretary of State at the Ministry of Justice in the Prodi government; in 2013 he was re-elected to the Senate in the ranks of the Democratic Party, remaining in office until 2018. Awarded the Premiolino in 2025, he has published among others: Solidarity, selfishness. Good actions, uncertain movements, new conflicts (1990), Italian Terrorists. The Red Brigades and Total War 1970-2008 (2008), A soul for the PD. The left and sad passions (2009), Music is light. A tale of half a century of songs (2012), Body and Soul (2016), The meaning of life. Conversations between a religious man and a non-believer (with V. Paglia, 2021), Abolishing prison. A reasonable proposal for the security of citizens (with S. Anastasia, V. Calderone, F. Resta, 2022), Policeman-Sexantotto. Violence and democracy (with G. Lettieri, 2023) and The disappearance of colours (2024), in which he recounts the progressive loss of sight until blindness.