Although the presidency is a nonpartisan office as guarantor of Italy's Constitution, Napolitano was a longtime member of the Italian Communist Party (and of its post-Communist social democratic successors, from the Democratic Party of the Left onwards). He was a leading member of a modernizing faction on the right of the party. First elected to the Chamber of Deputies in 1953, he took an assiduous interest in parliamentary life and was President of the Chamber of Deputies from 1992 to 1994. He was Minister of the Interior from 1996 to 1998 under Romano Prodi.