The unification of Italy was driven by two forces. The first was the centuries old strategy of the Royal House of Savoy and its supporters to do whatever was necessary to rule more territory. Reading the medieval history of Western Europe, one gets the impression that delegates from the House of Savoy sat in the corner during every treaty negotiation among the great powers and when those powers could not decide which of them should control a certain province, they threw it, like a bone, to the House of Savoy.
Prior to unification, the various political entities of Italy had been fragmented along lines of economics, language, class, historical rivalries, and intrigue. Unification made this worse especially because the people themselves were not consulted about the idea (which was wise since they probably would have said, “no.") Economic consolidation created unemployment and as luck would have it, due to overproduction, the wine market collapsed, ruining many. From its very beginning, Italy has been close to what we call today "a failed state." Point of fact, the whole thing was a bad idea. Making everything more difficult, approximately 80% or more of the ‘new’ Italian people were illiterate.
The country as a whole proved ungovernable, just as many of its constituent pieces, mainly in the South, had proved ungovernable. If the people didn't want a democratic state then they would get an authoritarian state, which is what happened. The paramilitary carabinieri, created decades before by the House of Savoy, enforced order along with the army, both of these institutions being dominated by loyalists of the Royal House.
[Image courtesy of Wikipedia.]