The history of Italy since Napoleon’s first arrival on the peninsula has been told many times, most memorably by Denis Mack Smith. Italy is, after all, just about the best story in modern European history. It’s so good because it’s so unexpected. In 1796, the idea that Italy would be united within 75 years was ridiculous. How could a nation that was merely a “geographic expression” ever bring together irregular freedom fighters with educated aristocrats and peasant bandits to overthrow the most powerful forces of continental Europe, namely the French, the Austrians and the heavily protected Papal states?

Sadly, it was a lot more complicated than the romantic narrative of the 19th century would have us believe. Unification didn’t bring unity, and it quickly became clear that patriotism had been a front for other issues: expansionism, republicanism, anticlericalism. Giuseppe Garibaldi was, in part, so idolised by Italians because he seemed so far removed from the uninspiring spectacle of Italian politics.

A large part of The Force of Destiny (the title is borrowed from a Verdi opera) is an attempt to understand what “Italy” has meant to the many regions of the peninsula, and to ask whether the concept of the Italian nation has ever satisfied what Duggan calls the human “need to owe primary allegiance to a collective body of one kind or another”. The answer to this question is often a blunt “no”. What is striking when reading about successive attempts to impose the northern king’s will on the southerners of Calabria, Sicily and Basilicata between the 1870s and the 1890s is how much they mirror contemporary events in Iraq. Resistance was orchestrated by a huge (Bourbon) bureaucracy that had been suddenly removed from power, and was fuelled by religious disgust at the devilish libertarians and by resentment over the lack of improvement in the lives of your average, impoverished peasant. It really did appear, as the great patriot Ugo Foscolo had written long before, that “all Italians are exiles in Italy”. The country appeared unwieldy, divided and forever fratricidal.

Another constant of the book is Italy’s yearning for martial victory. Following the glories of the Risorgimento, Italians had a desperation to demonstrate that they were as courageous and brilliant as Garibaldi had made them believe they were. Time and again, Italy tried to provoke a fight only to suffer humiliation: not merely against European opposition, but also against indigenous troops in Ethiopia at Adua (1896). Then there was Caporetto (1917), the humiliation of the first world war which was so terrible that it caused one of the great patriots, Leopoldo Franchetti, to commit suicide. Italy, it seemed, just couldn’t win. The country was constantly trying to prove Bismark’s insult wrong, and yet proving it apt each time. Italy, he said, “has a large appetite, but poor teeth”.

Before unification the country had been portrayed as a wounded, weeping, betrayed woman. Even afterwards, it remained the wronged underdog, forever spurned or beaten. Politicians and sociologists throughout the 19th century kept asking, “Who is to blame?”, and often came up with the answer nobody wanted to hear. “God save Italy,” wrote Massimo d’Azeglio, “not from foreigners but from Italians!” Many patriots lamented the scioltezza (“nimbleness”) of Italians, or “the rhetoric that eats our bones”, or else the “cream of vanilla” aestheticism of the pastel-coloured country. Long before those laments, Stendhal had described what he called the “ patriotisme d’antichambre”, a sort of local pride that Italians felt for their bell towers but that never became a truly national pride. Italy, Duggan writes, was sometimes nothing more than “a willing suspension of disbelief”.

What the author does with this material is inspired. His book could easily have become a tragic narrative about a doomed nation – especially because you know what’s coming next: the betrayal of socialism by Mussolini, the betrayal of Christianity by Christian democracy, and the betrayal of free-market economics by Silvio Berlusconi. But it ends up turning the reader into an Italian patriot, too. Duggan so clearly captures the excitement and uniqueness of the Risorgimento, and describes so well the heroism and tragedies of Italian history, that you cheer for the brave patriots who keep trying to unite the country and throw off the yoke of tyranny.

Italy, Garibaldi wrote, “was the fatherland of the Scipios and the Gracchi, the nation that boasts the Vespers and Legnano... It can never be wholly without sons who can astound the world”. As if to prove the point, Duggan offers brilliant sketches of some of those astounding sons. People such as the bandit Fra Diavolo (Brother Devil), a habit-wearing resistance fighter to Napoleonic troops who was hunted down by Victor Hugo’s father, or Vincenzo Gioberti, that unusual combination of patriot and priest. For diehard fans of the Risorgimento, there’s plenty of “Cavour was furious . . .

Cavour was euphor-ic”, but Duggan also describes in depth the cultural backdrop and subtleties of changing political winds. Unusually for 650 pages of pretty serious history, it’s an enthralling, gripping read.

The force of destiny: A History of Italy Since 1796 by Christopher Duggan
Allen Lane £30 pp652
Buy the book here at the offer price of £27 (inc p&p)

Times Recommends

• Superfreakonomics by Steven D Levitt and Stephen J Dubner
• The Times picks the 50 best paperbacks of 2009
• Vincent van Gogh’s letters show the soul of the artist