After World War I (1914–1918), despite the Kingdom of Italy (1861–1946) being a full-partner Allied Power against the Central Powers, Italian nationalism claimed Italy was cheated in the Treaty of Saint-Germain-en-Laye (1919), thus the Allies had impeded Italy's progress to becoming a "Great Power". Thenceforth, the PNF successfully exploited that "slight" to Italian nationalism in presenting Fascism as best-suited for governing the country by successfully claiming that democracy, socialism and liberalism were failed systems. The PNF assumed Italian government in 1922, consequent to the Fascist Leader Mussolini's oratory and Blackshirt paramilitary political violence.