On wresting control, D’Annunzio pronounced himself “Commander of Fiume,” declared a state of war and imposed martial law. As a result, any resistance to D’Annunzio was considered unpatriotic and threatened with execution. This decision to use force to “liberate” Fiume did not help matters; in fact it made them worse. Besides leading to a climate of heroism in both the town of Fiume and in the Italian nationalist movements, these events led to widespread desertions in the Italian Armed Forces and divisions in public opinion. Seeing a hotbed of revolutionary activity, many revolutionaries, futurists, former soldiers, nationalists, anarchists and adventurers made their way to Fiume from around the globe. Fiume became the symbol of patriotic fervor, and the town was laid siege.

In June 1920, political elections led to the defeat of the Fascists and to the resumption of Italy’s premiership by the Liberal Giovanni Giolitti. This also led to a hardening of official attitudes towards D’Annunzio’s coup. On November 12, Italy and Yugoslavia concluded the Treaty of Rapallo, under which Fiume was to be an independent state under a regime acceptable to both.On the heels of the treaty, D’Annunzio was asked to abandon Fiume. As neither the Army nor the Navy could show him any overt support any longer, it would have been a wise thing for him to do. Nonetheless, D’Annunzio’s reaction was typically colorful and of questionable judgment: He declared war on Italy. This in turn invited the bombardment of Fiume by Italian royal forces, and led to D’Annunzio’s inevitable surrender at the end of the year.

Italian troops took over in January 1921. The election of an autonomist-led assembly for the territory did not put an end to the Fiume question: A brief Italian nationalist takeover ended in the intervention of an Italian royal commissioner, and a short-lived local Fascist takeover in March 1922 brought on a third Italian military occupation. Seven months later, Italy herself fell under Fascist rule.