Final answer:
Mussolini promised to bring political stability to Italy when the Black Shirts marched on Rome, utilizing this as a platform to establish his fascist regime, which dismantled democratic institutions and enforced totalitarian rule.
Step-by-step explanation:
When the Black Shirts marched on Rome, Benito Mussolini presented himself as the only man capable of bringing political stability to Italy. He did this by promising order and returning Italy to a state of greatness, tapping into the frustrations and desires of different social and economic groups for a unified and powerful nation. His rise to power was marked by the end of democracy; the totalitarian regime that followed was anti-socialist, anti-liberal and enforced strict loyalty to the state. Mussolini, who called himself 'Il Duce', swiftly curtailed democratic freedoms, outlawed political parties, and suppressed opposition to establish fascist control, advocating for a strong authoritarian leadership over the perceived ineffectiveness of parliamentary governance.