Rome, February 8 - Italian President Giorgio Napolitano, a former member of the country's Communist Party, has admitted in an article for Vatican daily L'Osservatore Romano that the ideology he once believed in failed. "It was impossible - except for small circles of people who were nostalgic on the theoretical level and hard-core political extremists - to avoid the historical certification of the failure of the Communist economic and social systems," Napolitano wrote in an article that will be published in Saturday's edition of the paper. After the fall of the Berlin wall, the rump of Italy's Communist Party changed into a social democratic party, the Democrats of the Left (DS). Napolitano was a DS member when he was named the head of state on 2006. The DS merged with the centrist Margherita (Daisy) party to form the mainstream centre-left Democratic Party in 2007.