Mussolini launched Il Popolo d'Italia, a new newspaper, in October of 1914.  In his editorials, he came out in full support of Italian intervention into World War I.  By December, he had denounced traditional "red" socialism, for failing to recognize that the war had made the nation more important than class distinction, coming out fully as a "yellow," or national socialist.

Class cannot destroy the nation...

"The nation has not disappeared," he said, in a speech he gave about nationhood.  "We used to believe that the concept was totally without substance.  Instead, we see the nation arise as a palpitating reality before us!  Class cannot destroy the nation.  Class reveals itself as a collection of interests... but the nation is a history of sentiments, traditions, language, culture and race.  Class can become an integral part of the nation, but one cannot eclipse the other."

While denouncing orthodox socialism and its exclusive focus on class conflict, he affirmed that he was a national socialist in the tradition of Giuseppe Garibaldi, Giuseppe Mazzini and Carlo Pisacane.  

National socialism formed the basic principals of his newly
formed political movement...

French socialists, who supported dissident Italian socialists that favored intervention into the war in support of the French, financed Mussolini, as  did Italian armament company, Ansaldo, who helped fund his newspaper.

National socialism formed the basic principals of his newly formed political movement, the Fasci d' Azione Rivoluzionaria, who referred to themselves as Fascisti.  Although small in numbers, their movement was regularly attacked by radical socialists opposed to Italy's intervention into the war.  These attacks were so violent that even democratic socialists such as Anna Kuliscoff, themselves opposed to the war, said the Italian Socialist Party had gone too far in its efforts to silence opponents.  These attacks would later shape Mussolini's views in support of the use of political violence, a tactic that would eventually lead to his rise to power.  

He was promoted "for merit in war"...

Believing in action, Mussolini volunteered, himself, to join the Italian army.  He was initially turned away, due to his history of radical socialism, but was called back on August 31, 1915 and reported to an elite unit, the Bersaglieri.  His service was admirable, as illustrated by an Italian Inspector General Report which stated, "He was promoted to the rank of corporal 'for merit in war.'  The promotion was recommended because of his exemplary conduct and fighting quality, his mental calmness and lack of concern for discomfort, his zeal and regularity in carrying out his assignments, where he was always first in every task involving labor and fortitude."

Wounded in February of 1917, when a mortar exploded nearby, he was evacuated from battle and was later discharged from the military, due to the severity of his injuries.  He resumed his role as editor of Il Popolo d' Italia, but the sacrifice for country and discipline he had learned in the military would stick with him throughout his life.  

The beginning of 1914 brings the start of World War I and a split in European Socialism.  Traditional socialists believed in the primacy of class over country and followed the "Red" socialism, or Communist ideals, of Karl Marx.  But, so-called "Yellow Socialists" believed that the traditional views had become stagnate and had not advanced the cause of the proletariat, or workers class.  They felt the creation of a classless, nationless mob would reduce the living standards of everyone, including the workers they sought to help.  While still believing in the cause of advancing the proletariat, they sought a new form of socialism that had the state heavily regulate both business and labor for the benefit of society as a whole.  World War I brought this new approach to the forefront. 

Traditional "red" socialism had become stagnate...

Socialists in Great Britain, France, Germany and Austria tended to follow the new "yellow" approach to socialism, feeling patriotic fervor and seeking their country's entry into the war.  Italian socialists were divided, with prominent members such as  Alceste De Ambris, Filippo Corridani and Angelo Oliviero Olivetti supporting Italy's entry into World War I, while the party itself took a more traditional view and opposed their country's involvement. 

World War I would be a revolutionary war... 

Mussolini, at first, supported his party's position, writing an article in 1914 entitled "Down With The War.  We Remain Neutral!"  But, his views changed with further study and review of the issue.  He began to see opportunities for both himself and his fellow socialists.  First, he saw the chance to liberate thousands of Italians from Austro-Hungarian rule, as well as to bring down the Hapsburg and Hohenzollern dynasties, whom he felt had oppressed socialism within their realms.  He further accused the Central Powers of being imperialist and said their overthrow, as well as the repression of Ottoman Turkey, would create conditions favorable to the working class.  He also predicted that the mobilization of troops needed for the war would lead to a social revolution in Tsarist Russia, ending that authoritarian monarchy.  For Mussolini, World War I would be a revolutionary war that would unite all Italians and socially change Europe in favor of the lower working classes.  His new views caused him to be expelled form the Italian Socialist Party, but his allegiance never faded.  He would later claim that he never abandoned his Left Wing ideals stating, "Do not believe, even for a moment, that by stripping me of my membership card you do the same to my Socialist beliefs, nor that you would restrain me of continuing to work in favor of Socialism and the Revolution."

Benito Mussolini emigrated to Switzerland in 1902, where he became active in the Italian socialist movement.  He worked for the L'Avvenire del Lavoratore newspaper, served as secretary of the Italian workers union in Lausanne, gave speeches and organized meetings for socialist activists and sympathizers.  He continued to study socialist philosophers including Friedrich Nietzche, Vilfredo Pareto of the Lausanne School, and the syndicalist Georges Sorel.  It was Sorel's ideas about the need for a violent overthrow of liberal democracy and capitalism through violence, general strikes and direct action that highly influenced Mussolini's own political views and were later incorporated into his Fascist movement.   He also credited Christian socialist Charles Peguy and the syndicalist Hubert Lagardelle as being some of his mentors.

Mussolini denounced Italy's "imperialist war" in Libya

Mussolini spent two weeks in jail in 1903, after having been arrested for advocating for a general strike.  The Swiss government deported him back to Italy, but he returned after falsifying his papers.  He studied at the University of Lausanne and was arrested, a year later, in Geneva, Switzerland.  

In February of 1909, he moved to the Italian-speaking city of Trento which was then part of the Austro-Hungarian Empire.  There, he worked in the office of the local socialist party.  

Mussolini returned to his hometown in Italy, in 1910, to edit the weekly newspaper, Lotta di Classe (The Class Struggle).  He also published "Il Trentino veduto da un Socialista (Trentino as seen by a Socialist), in the Left-Wing periodical La Voce.

Mussolini described Marx as the "greatest of all theorists of socialism"

In September of 1911, he denounced Italy's "imperialist war" in Libya, as a participant in a socialist-led riot.  This protest caused him to be arrested and to spend five months in jail.  But, it also built his credibility and led to his becoming editor of the Socialist Party newspaper, Avanti.

Describing Marx as the "greatest of all theorists of socialism," Mussolini fully considered himself a follower of the Communist founder.  Vladimir Lenin would later criticize Italian socialists for expelling him from their ranks.  So, why did he separate from the Italian Socialist Party?  Did his political philosophy really change?  We shall see that his passion for socialism remained strong and true.  It was his philosophy about Italian involvement in World War I that evolved.