The unification of Italy in the 19th century was at first greeted with enthusiasm, but this soon evaporated among the Sicilians. Namely, the island was poor and many Sicilians felt the central government neglected them just as badly as foreign rulers had, and things got even worse when Mussolini’s Fascists rose to power in the 1930s. Italy’s entry into World War II on the Axis side caused even more resentment, and a Committee for the Independence of Sicily was founded in April 1942. When the American-led Allied invasion of the island occurred in July 1943, the island became the scene of heavy fighting. Tens of thousands of people were killed and there was much material damage. In addition, Mussolini’s previous crackdown on the Mafia was exploited by the Americans, and the Mafia provided them with military intelligence. However, this also led to the Mafia re-establishing its influence after the end of World War II.
The generally poor treatment afforded to the island by Italy as well as the fear of a communist takeover prompted a group of enterprising Sicilians named the Sicilian Independence Movement and led by the prominent bandit (or folk hero, depending on who you ask) Salvatore Giuliano, to petition U.S. president Harry Truman. Their request was no less than to join the United States, claiming Sicily would provide an effective deterrent to Soviet expansion on the Mediterranean. These initiatives also had some support among the numerous Sicilian emigrants in the USA.
It appears the U.S. actually had a contingency plan which would have involved the annexation of Sicily had communists won the elections in mainland Italy (which indeed almost happened). However, infighting among the Movement’s ranks and the central government’s granting of further concessions to Sicily resulted in its demise. Had the proposal been accepted, Sicily would have become the 49th U.S. state, preceding Alaska and Hawaii.