where it regularly won the local administrative elections, and in some of the industrialised cities of Northern Italy. At the city government level during the course of the post-war period, the PCI demonstrated in cities like Bologna and Florence their capacity for uncorrupt, efficient and clean government. After the 1975 Italian local elections, the PCI was the strongest force in nearly all of the municipal councils of the great cities. From the 1950s to the 1960s The Soviet Union's brutal suppression of the Hungarian Revolution of 1956 created a split within the PCI. The party leadership, including Palmiro Togliatti and Giorgio Napolitano (who in 2006 became President of Italy), regarded the Hungarian insurgents as counter-revolutionaries as reported at the time in l'Unità, the official PCI newspaper. Giuseppe Di Vittorio, chief of the communist trade union Italian General Confederation of Labour (CGIL), repudiated the leadership position, as did prominent party member Antonio Giolitti and Italian Socialist Party national secretary Pietro Nenni, a close ally of the PCI. Napolitano later hinted at doubts over the propriety of his decision. He would eventually write in From the Communist Party to European Socialism. A Political Autobiography (Dal Pci al socialismo europeo. Un'autobiografia politica) that he regretted his justification of the Soviet intervention but quieted his concerns at the time for the sake of party unity and the international leadership of Soviet Communism. Giolitti and Nenni went on to split with the PCI over this issue. Napolitano became a leading member of the miglioristi faction within the PCI that promoted a social-democratic direction in party policy. In the mid-1960s, the United States Department of State estimated the party membership to be approximately 1,350,000, or 4.2% of the working age population, making it the largest Communist party in per capita terms in the capitalist world at the time and the largest party at all in the whole of Western Europe with the Social Democratic Party of Germany. United States government sources said that the party was receiving $40–50 million per year from the Soviets when their investment in Italy was $5–6 million. Although the PCI relied on Soviet financial assistance more than any other Communist party supported by Moscow, declassified information shows this to be exaggerated. According to the former KGB archivist Vasili Mitrokhin, Longo and other PCI leaders became alarmed at the possibility of a coup in Italy after the Athens Colonel coup in April