linguistic:translation
Formation of the National Fascist Party

By the time he returned from service in the Allied forces of World War I, Mussolini was convinced that socialism as a doctrine had largely been a failure. In 1917 Mussolini got his start in politics with the help of a £100 weekly wage (the equivalent of £7100 as of 2020) from the British security service MI5, to keep anti-war protestors at home and to publish pro-war propaganda. In early 1918 Mussolini called for the emergence of a man "ruthless and energetic enough to make a clean sweep" to revive the Italian nation. On 23 March 1919 Mussolini re-formed the Milan fascio as the Fasci Italiani di Combattimento (Italian Combat Squad), consisting of 200 members.

The ideological basis for fascism came from a number of sources. Mussolini drew from the works of Plato, Georges Sorel, Nietzsche, and the economic ideas of Vilfredo Pareto. Mussolini admired Plato's The Republic, which he often read for inspiration. The Republic expounded a number of ideas that fascism promoted, such as rule by an elite promoting the state as the ultimate end, opposition to democracy, protecting the class system and promoting class collaboration, rejection of egalitarianism, promoting the militarisation of a nation by creating a class of warriors, demanding that citizens perform civic duties in the interest of the state, and utilising state intervention in education to promote the development of warriors and future rulers of the state.

The idea behind Mussolini's foreign policy was that of spazio vitale (vital space), a concept in Italian Fascism that was analogous to Lebensraum in German National Socialism. The concept of spazio vitale was first announced in 1919, when the entire Mediterranean, especially so-called Julian March, was redefined to make it appear a unified region that had belonged to Italy from the times of the ancient Roman province of Italia, and was claimed as Italy's exclusive sphere of influence. The right to colonise the neighbouring Slovene ethnic areas and the Mediterranean, being inhabited by what were alleged to be less developed peoples, was justified on the grounds that Italy was allegedly suffering from overpopulation.

Borrowing the idea first developed by Enrico Corradini before 1914 of the natural conflict between " plutocratic " nations like Britain and "proletarian" nations like Italy, Mussolini claimed that Italy's principal problem was that "plutocratic" countries like Britain were blocking Italy from achieving the necessary spazio vitale that would let the Italian economy grow. Mussolini equated a nation's potential for economic growth with territorial size, thus in his view the problem of poverty in Italy could only be solved by winning the necessary spazio vitale.

Though biological racism was less prominent in Italian Fascism than in National Socialism, right from the start the spazio vitale concept had a strong racist undercurrent. Mussolini asserted there was a "natural law" for stronger peoples to subject and dominate "inferior" peoples such as the "barbaric" Slavic peoples of Yugoslavia. He stated in a September 1920 speech:

When dealing with such a race as Slavic—inferior and barbarian—we must not pursue the carrot, but the stick policy... We should not be afraid of new victims... The Italian border should run across the Brenner Pass, Monte Nevoso and the Dinaric Alps... I would say we can easily sacrifice 500,000 barbaric Slavs for 50,000 Italians...

In the same way, Mussolini argued that Italy was right to follow an imperialist policy in Africa because he saw all black people as "inferior" to whites. Mussolini claimed that the world was divided into a hierarchy of races (though this was justified more on cultural than on biological grounds), and that history was nothing more than a Darwinian struggle for power and territory between various "racial masses". Mussolini saw high birthrates in Africa and Asia as a threat to the "white race". Mussolini believed that the United States was doomed as the American blacks had a higher birthrate than whites, making it inevitable that the blacks would take over the United States to drag it down to their level. The fact that Italy was suffering from overpopulation was seen as proving the cultural and spiritual vitality of the Italians, who were thus justified in seeking to colonise lands that Mussolini argued—on a historical basis—belonged to Italy anyway. In Mussolini's thinking, demography was destiny; nations with rising populations were nations destined to conquer; and nations with falling populations were decaying powers that deserved to die. Hence, the importance of natalism to Mussolini, since only by increasing the birth rate could Italy ensure its future as a great power. By Mussolini's reckoning, the Italian population had to reach 60 million to enable Italy to fight a major war—hence his relentless demands for Italian women to have more children.

Mussolini and the fascists managed to be simultaneously revolutionary and traditionalist; because this was vastly different from anything else in the political climate of the time, it is sometimes described as "The Third Way". The Fascisti, led by one of Mussolini's close confidants, Dino Grandi, formed armed squads of war veterans called blackshirts (or squadristi) with the goal of restoring order to the streets of Italy with a strong hand. The blackshirts clashed with communists, socialists, and anarchists at parades and demonstrations; all of these factions were also involved in clashes against each other. The Italian government rarely interfered with the blackshirts' actions, owing in part to a looming threat and widespread fear of a communist revolution. The Fascisti grew rapidly; within two years they transformed themselves into the National Fascist Party at a congress in Rome. In 1921, Mussolini won election to the Chamber of Deputies for the first time. In the meantime, from about 1911 until 1938, Mussolini had various affairs with the Jewish author and academic Margherita Sarfatti, called the "Jewish Mother of Fascism" at the time.