Lawyer qualified before higher Courts. He carried out activities before common judges, the Constitutional Court and European Courts, especially in the field of constitutional law.
Former judge (1996-2005) and president of the Constitutional Court (2004-2005).
Former professor of public law, parliamentary law, regional law, constitutional law, constitutional justice at the Universities of Padua (Verona branch), Sassari, Pavia, Bologna and Milan, from 1966 to 2009.
Former member of legislative technical-scientific committees and study committees of various Italian Regions and Autonomous Provinces.
Former president, for a three-year term, of the Italian Association of Constitutionalists, and, for a four-year term, of the Higher School of the Judiciary.
He carried out voluntary work at the legal branch of the Bollate prison.
He is the author of innumerable scientific publications (books, essays, encyclopedia entries, case law reviews, chapters of manuals, articles) on various subjects of constitutional law and public law, in particular on budget process and spending power, public administration, regional autonomy, the working of the Italian form of government, constitutional justice, fundamental rights.
Commentator on constitutional issues with the newspapers Corriere della Sera and Il Sole 24 Ore.