His political commitment began in 1963, when he joined the Italian Communist Youth Federation (Fgci), of which he was National Secretary from 1975 to 1980. The first card of the Italian Communist Party (PCI) is from 1968. he Joins the Central Committee in 1979 at the 15th congress, at the following congress in 1983 he is in the Direction, in 1986 in the secretariat. He is among the young leaders of the "turning point" who, in 1989, with Achille Occhetto, transformed the PCI into the Democratic Party of the Left (PDS). At the birth of the new party, in 1990, he became its political coordinator. On 1 July 1994 he was elected National Secretary of the PDS. He entered the Chamber of Deputies for the first time in 1987, elected in the district of Lecce-Brindisi-Taranto. In 1992 he is the leader. re-elected, he assumes the position of President of the group of deputies of the PDS. In 1994 he was a candidate, with the new single-member electoral system, in the 11th college of Puglia, where he was reconfirmed on 21 April 1996. Professional journalist, he collaborated on "Città futura", "Rinascita" and "l'Unità" of which he was director from 1988 to 1990. He is currently President of the Italianieuropei Foundation. From 21 October 1998 to April 2000 he held the office of President of the Council of Ministers. In December 2000 he was elected President of the Left Democrats. From October 2003 to August 2012 he was vice-president of the Socialist International, a position to which he was elected in the Congress of Sao Paulo in Brazil and reconfirmed during the Congress of Athens in July 2008. In June 2004 he was elected to the European Parliament where he held the position of President of the Permanent Delegation for relations between the European Union and Mercosur. On 9 April 2006 he was elected deputy on the list of the Olive tree in the Puglia district. On 17 May 2006 he was appointed Vice President and Foreign Minister in the Prodi government. On 22 April 2008, he was confirmed as Deputy of the XVI Legislature in the XXI Puglia District on the Democratic Party lists. From January 2010 to March 2013 he was President of the Parliamentary Committee for the Security of the Republic (COPASIR). From June 2010 to June 2017 he was President of the Foundation of European Progressive Studies (FEPS).