How not to run a country

English historians of foreign societies, an enduring and prolific species, divide into two groups. Some, like the late Richard Cobb, acquire a second identity, learning to live, talk and above all think like their adopted subjects. A larger number, however, remain irretrievably English, sceptical, observant, not always at ease with their new language but widely admired abroad for their scholarship, judgement and, in countries where professorial chairs are bartered between parties, their lack of political affiliation.

One of the most distinguished members of the second group is Denis Mack Smith, who has dominated the historiography of modern Italy for more than 40 years. His first book, Cavour and Garibaldi 1860, overturned traditional interpretations of the Risorgimento, among other ways by relegating Cavour from the status of statesman to the role of lucky and unscrupulous trickster; and his subsequent works, especially those on Sicily, Mussolini and the monarchy, extended the iconoclasm to other areas. Certain Italian historians have never forgiven him for the sin of taking away the Risorgimento's "soul".

Modern Italy is an enlarged edition of Mack Smith's equally controversial second book, commissioned in the 1940s by an American publisher who went bankrupt while in possession of the sole typescript. Although presumed lost, it reappeared several years later and was published by Laterza and Michigan University. The Italian version generated noisy polemics and annual new editions while its English companion was comparatively neglected: Yale has thus performed a notable service in providing a fresh edition of a magisterial work which remains important after half a century.

Modern Italy punctured the myth of the Risorgimento as an heroic national struggle, a war of liberation gained by the self-sacrifice of a people intent on unity and independence. The "national struggle" was in fact a contest between elites, a succession of little civil wars played out against a background of Great Power rivalry. It owed its success largely to a combination of luck, diplomacy and various military campaigns fought between the French, the Austrians and the Prussians. Heroism and self- sacrifice were not substantial factors: then, as since, the Italians were pretty sensible about not letting themselves be killed for ideals. As Mack Smith pointed out in a later book, Italy lost more men during a single colonial disaster (the Battle of Adowa against the Abyssinians in 1896) than in all the wars of the Risorgimento.

One of the book's strengths is the connections it makes between the politics of liberal Italy and the politics of Mussolini, especially during Crispi's "years of aggrandisement and megalomania". Historians had traditionally seen fascism as an aberration, an unfortunate but temporary diversion from the path of Gladstonian constitutional development. Mack Smith, by contrast, saw it as a product of the Risorgimento's essential flaw - to have proclaimed a nation without really bothering to forge one - and of the mistakes and practices of politicians afterwards. Much of Mussolini's behaviour was anticipated by the prime ministers of united Italy and their boorish Piedmontese sovereigns. Fascist views on national prestige, imperial expansion and parliamentary government were inspired by Crispi's policies at the end of the 19th century.

Modern Italy is not simply a disparagement of politicians and a catalogue of their blunders. Mack Smith respects the incorruptible Ricasoli and resurrects Mazzini as an authentic nationalist hero; he admires Giolitti for his reforms and concern with social welfare, and he praises the skills and principles of De Gasperi. Nevertheless, in its cumulative effect this is a profoundly depressing book, a long and eloquent statement on how a country should not be governed. No wonder a British newspaper advised the leaders of independent Ghana to read it so that they could avoid making similar mistakes.

For this edition the author has added 70 pages chronicling the last 50 years of Italian history. Although few serious historians like to judge contemporary politics, it is no doubt satisfying for them to observe how events continue to illustrate trends they had identified half a century earlier. Italy is now a rich and vibrant country, but its prosperity owes almost nothing to its politicians. While its dreams of international glory were buried with Mussolini, many of its current internal problems have an ancestry going back to the foundation of the state: the corruption of politics, the weaknesses and instability of coalition rule, the failure (partly from incompetence, partly from more sinister reasons) to confront the Mafia effectively. And the Risorgimento's chief defect - that it did not achieve a true reconciliation of north and south - is still with us. What else is the Northern League but a crude contemporary manifestation of Azeglio's anxiety about uniting with the south, that fusion with Naples which he predicted would be "like sharing a bed with someone who has smallpox"?

These last chapters are written with Mack Smith's customary blend of narrative force, stark objectivity and permeating irony. The antimacksmithiani will complain as usual of his "austere", "puritanical" and even "contemptuous" view of Italians, but the rest of us should be grateful that he has focused his sceptical intelligence on the present. The pages on the ineffable Berlusconi demonstrate that here is a writer still at the height of his powers and in control of his terrain.

The publication of the book (and its predecessor) in the 1950s upset a well-defended orthodoxy that had been entrenched for almost a century. That it can be republished now with only minor amendments to the original text is a testament to Mack Smith's greatness as an historian.