Norberto Bobbio

Key Italian political philosopher whose vigilance and clarity helped guide his country's postwar democracy

Norberto Bobbio, who has died aged 94, was Italy's leading legal and political philosopher, and one of the most authoritative figures in his country's politics. His status was marked by the Italian president's immediate departure for Turin to be among the first mourners, and an extensive discussion of his writing in the media.

Bobbio's life and work were conditioned by the vicissitudes of his country's democracy in the 20th century. The experience of fascism, the ideological divisions of the cold war, and the transformation of Italian society during the 1960s and 1970s - which he described so evocatively in his Ideological Profile Of Italy In The Twentieth Century (1969) - prompted and enriched his passionate defence of the constitutional "rules of the game" against those who denied their relevance or would overturn them for reasons of pragmatic convenience.

Bobbio was born into a relatively wealthy, middle-class Turin family. He has characterised their sympathies as "filo-fascist", regarding fascism as a necessary evil against the supposedly greater danger of Bolshevism. At school and university, however, he became acquainted with many of the leading lights of the largely antifascist Turin intelligentsia.

These included the novelists Cesare Pavese and Carlo Levi, his future publisher Giulio Einaudi, the critic Leone Ginsburg and the radical politician Vittorio Foa. He never met the two best-known martyrs of Turin's antifascist movement - Antonio Gramsci and the revolutionary liberal Pietro Gobetti - though he became director of the centre dedicated to the latter's memory, and his own papers have been housed there with Gobetti's.

Although Bobbio was not active in resistance, he was led to a position of passive, yet profound, intellectual opposition. In his autobiography (1997), he described this first half of his life as belonging to his prehistory. However, his stress on the importance of civil and political liberties derived much of its power from his having lived his formative years under a government that had suppressed them - even forcing him to pledge allegiance to the regime to save his job, an action he later deeply regretted.

The fall of Mussolini in September 1943 catapulted Bobbio, along with so many of his generation, from total exclusion from political life into active involvement with it. Since the late 1930s, he had been associated with the liberal socialist movement, which became part of the Party of Action, the main non-communist resistance grouping. He played a minor role, but did engage in some clandestine activity against the German occupation, and was briefly imprisoned from 1943 to 1944.

Although intellectually influential, the azionisti lacked a popular base. Thus, Bobbio stood unsuccessfully in the 1946 constituent assembly elections, but then returned to academic life. However, the party's slogan, "Justice and liberty", captures the central theme of much of his subsequent work - how to unite the liberties beloved of liberals with the socialist demand for social and economic justice. It was this commitment to these twin ideals that made him the perfect critical interlocutor between the Communist party (CPI) and the various governmental parties gathered around the Christian Democrats, and gave him such influence within political life.

Bobbio had taken degrees in jurisprudence and philosophy at Turin. His first book, The Phenomenological Turn In Social And Legal Philosophy (1934), had been followed by a monograph on The Use Of Analogy In Legal Logic (1938) and, in 1944, by a critical study of existentialism, and the first of his books to be translated into English, The Philosophy Of Decadence. He taught jurisprudence at the University of Camerino, then at Siena, and was appointed to a chair at Padua in 1940.

In 1948, he replaced his teacher, Gioele Solari, as professor of legal philosophy at Turin, where he remained until 1972. During this period, he gradually dissociated himself from the broadly idealist approach to philosophy then dominant in Italian universities. He was friendly with the philosopher of science Ludovico Geymonat (also based at Turin) and, with him, helped set up the interdisciplinary centre for methodological studies.

He now set himself the task of elaborating a general theory of the practice and validity of law, breaking with the attempts of most contemporary Italian philosophers to offer a speculative philosophy of the idea and morality of law.

In elaborating his version of legal positivism, Bobbio drew on the writings of Hans Kelsen, whose work he had come across as early as 1932. This research ultimately bore fruit in a number of books based on his Turin lectures, of which the most important are A Theory Of Judicial Norms (1958) and A Theory Of The Legal Order (1960), and studies of Locke, Kant and legal positivism. Between 1955 and 1970, he also published three collections of essays. These writings had a similar place in Italian academic legal circles to the work of HLA Hart, the late Oxford professor of jurisprudence, and both men, at different times, expressed their mutual esteem for each other to me.

Bobbio's legal studies fed into his political writings. Influenced again by Kelsen, he adopted a procedural view of democracy as consisting of certain minimal "rules of the game", such as regular elections, free competition between parties, equal votes and majority rule.

His theory was enriched by a strong, realist current, deriving partly from Hobbes and partly from the Italian pioneers of political science, such as Gaetano Mosca and Vilfredo Pareto (whose reputation he did much to resurrect). He had produced the first Italian edition of Hobbes's De Cive in 1948, and later dedicated numerous studies to the English philosopher, a collection of which were published in 1989 (and appeared in English a couple of years later). He drew on Hobbes to modify what he now saw as unsatisfactory elements of his earlier Kelsenism.

Bobbio regarded Kelsen as caught uncomfortably between a purely formal account of law and a substantive position grounded in what he called the "basic norm" underlying all law. The missing dimension was the institutional context of law-making, and its relationship to the exercise of power. Unlike earlier legal positivists, such as John Austin, Bobbio did not thereby equate law with the commands of the sovereign; his point was rather that law and rights were best conceived as a historical achievement belonging to a particular form of state.

Bobbio's shift from a pure theory of law to a concern with its political embodiment was marked by his moving to a chair in the newly created faculty of political science in Turin in 1972, where he remained until the then statutory retirement age of 75 in 1984. The essays from this period were later collected as The Future Of Democracy: A Defence Of The Rules Of The Game (1984) - to my mind, the most original of his books - State, Government And Society (1985) and The Age Of Rights (1990), all of which appeared in English.

Bobbio's linking of the rule of law and rights to the distribution of power produced by liberal democracy informs his contributions to the political debates of the period. His prime concerns, from the 1950s onwards, were to enter into dialogue with the PCI and build a social democratic opposition in Italy. Indeed, the latter could only be achieved if the PCI, the country's largest grouping on the left, could be weaned away from the Soviet Union and converted to liberalism.

It is no accident that Bobbio published the first (and, for some years, the only) Italian study of Karl Popper's The Open Society And Its Enemies as early as 1946, in a journal appropriately entitled Il Ponte (The Bridge); he was a founding member of the European Society of Culture, which had this critical dialogue as a goal. His first book of political essays, Politics And Culture (1955), consisted largely of a debate with the Marxist philosopher Galvano della Volpe, and over whether socialist legality could be based on anything other than the traditional liberal rights - discussion that ultimately prompted the intervention of PCI leader Palmiro Togliatti.

This theme resurfaced in Bobbio's next major foray into politics, in the 1970s. The spur this time came from the historic compromise between the PCI and the Christian Democrats, whereby the PCI, which had a strong foothold in local government and was the main opposition party, was given access to state positions while being denied participation in central government.

PCI leaders were worried that terrorist violence, some of it certainly promoted by the security services, might be used as an excuse for a rightwing coup should they appear to be too strong - a fear reinforced by the fate of Salvador Allende's Popular Unity government in Chile. They sought to make themselves non-threatening to the status quo, while strengthening their position within the Italian political system - a tactic they associated with Gramsci.

Bobbio's interventions challenged the coherence of this Eurocommunist strategy of a third way between liberalism and Soviet communism. In a series of essays, published as Which Socialism? (1976), he criticised Marxism for lacking a theory of the state or democracy, and implicitly urged the PCI to become a social democratic party.

He was an equally harsh critic of the corruption of Italian politics, and of the role of the non-communist Socialist party, under Bettino Craxi, in upholding that system and taking it to new depths. His first article following the collapse of the Soviet bloc was not be a piece of liberal triumphalism, but a reminder that the cause of social justice, which had inspired communism, remained as pressing as ever, and that liberals could not afford to ignore it. He later reiterated this thesis in his long essay Left And Right (1994), which entered the Italian bestseller lists, in which he argued that the search for a reconciliation between claims of liberty and equality still provided the key issue of modern politics, and the main dividing line between political parties.

Bobbio was also closely associated with the peace movement, another concern which bears a direct relation to his academic work. His view of the political character of law led him to recognise the need for a political theory of international relations. In a series of pathbreaking essays, he explored the possibility for global forms of democracy to give meaning to international law.

He was a passionate critic of nuclear weapons, which he saw as making war intrinsically unjust, and a member of the Bertrand Russell Foundation. His writings on this issue were collected in the volumes The Problem Of War And The Roads To Peace (1979) and The Absent Third (1989). He was not a pacifist, though many were surprised when he supported the first Gulf war - a position he defended in his book, A Just War? (1991), but later went back on.

An esteemed political commentator, who wrote regularly for the Turin-based daily La Stampa, Bobbio kept aloof from direct involvement in party politics, and refused invitations to stand as a senator. He took his teaching duties extremely seriously, and sympathised with that element of the 1960s student movement (of which his eldest son was a leader) that complained about the large numbers of Italian academics who engaged in extra-curricular activities to the detriment of their university responsibilities.

In the year of his retirement, however, he was nominated by the Italian president to one of the five life senatorships, and sat in the upper house as an independent socialist. Indeed, in 1992, he came close to being elected president as a compromise candiate. But he confessed to finding decision-making difficult; his talent was always spotting problems rather than solutions, and he was relieved that the bid failed. At the same time, he was deeply disappointed by the failure of the centre-left to establish its hold on Italian politics.

He became an outspoken critic of the current prime minister and media magnate Silvio Berlusconi, lamenting in 2001 how the second Italian republic appeared to lack any of the idealism of the first. Significantly, in his essays In Praise Of Meekness (1994), he turned his attentions to the non-political virtues and the issue of how to respond to evil in a corrupt world.

Bobbio's wife of 58 years, Valeria, died suddenly in 2001, though three sons survive him. He himself died as he had lived, with great dignity, instructing his doctors not to intervene when he was taken into hospital soon after Christmas. To his credit, he founded no school, while influencing many.

Noberto Bobbio, political philosopher, born October 18 1909; died January 9 2004.