Cavour was from Piedmont, which was a state in northern Italy still under the control of the Habsburg in the XIXth century. Because he was from the northern, european, civilized Italy states, it is questionable wether or not he wanted to create one nation along with the southern, more african-like, uncivilized Italy states. However, it can be shown that Cavour did want a unification of some sort for Italian states. To unify a nation to form a single state, a very strong nationalism is needed, which he showed by creating a local newspaper in 1847 bearing the name of the Italian unification movement (Il Risorgimento), as well as by causing a war with Austria jsut to get a free Italy. He also created a youth movement called the young Italy.
Gariboldi marched north, which could be seen as a threat to the Pope, which could make the European Great Powers react and march on Italy, which would go in the way of its unification. Plus, because Gariboldi unified the south of Italy, and because of the Mezziogiorno (the discrimination between the North and the South), there was a risk of a civil war. So Victo-Emmanuel II went to meet him with his army prepared for war. But when they met, Gariboldy gave up the southern Italy to the king of the northern Italy. Cavour had to accept this, because the liberal movement he cretaed, the young Italy, was much more popular in the south, and they could become very useful to free Italy from Austria's control. Now Italy was unified, except for bits of Lombardy and Venetia, which were still under the Habsburg. Then came the Crimean war. Cavour decided to send troops (20,000) to war to help the side which was to become the winner, so that Piedmont could have some part to play in the after war conference on the winner side. He realised it wouldn't be much but it allowed the Italians to gain some influence concerning the Balance of power in Europe. In this same war, Russia asked Austria for help because of the terms of the Holy Alliance from the Congress of Vienna, but seeing how the war was going, Austria didn't help the Russians, who never forgave them. Later on, when the Italians were about to throw out of Italy the last parts of the Habsburg,