How did plebiscites help Camillo Benso, count di Cavour annex central Italian states to Piedmont?

Plebiscites were instrumental in Camillo Benso, count di Cavour’s strategy to annex central Italian states to Piedmont by providing a veneer of popular legitimacy to the unification process, which helped overcome international opposition.

Following the Second Italian War of Independence, spontaneous uprisings occurred in central Italian duchies and the Papal Legations. Although Napoleon III initially opposed Piedmontese annexation of these territories, Cavour—who returned to office in January 1860—utilized plebiscites to confirm the local populations' desire for union with Piedmont.12

These votes were highly successful, yielding nearly unanimous support for annexation. By demonstrating that the desire for unification was a popular movement rather than merely a top-down conquest, Cavour was able to challenge the restoration plans of foreign powers and effectively integrate regions like Tuscany, Modena, Parma, and the Romagna into the expanding Piedmontese state. This process was later repeated in the south, where plebiscites in October 1860 were used to confirm the annexation of Sicily and Naples to Piedmont, ultimately leading to the declaration of the Kingdom of Italy in 1861.123