Squadrismo [skwaˈdrizmo] consisted of fascist squads who were led by the Ras from 1918 - 1924. As a movement it grew from the inspiration many Ras leaders found from Mussolini, but was not directly controlled by Benito Mussolini.
Squadrismo was mainly used to combat the growing Socialist movement which was a big opponent of Fascism. Fascist squads would participate in strikebreaking, organizing tax strikes in socialist controlled towns and intimidating voters at election time. In 1922, prominent Ras leaders such as Dino Grandi and Italo Balbo had taken control of many towns in the Po Valley such as Ferrara and Bologna.
Following the 'foot in the door' election of 1921, Mussolini sought to win some control over these autonomous squads through the pact of pacification with the PSI (socialist party). While there are different interpretations of Mussolini's primary reasoning for this pact, whether it was a return to his leftist roots; the ultimate goal of scaring the Ras into conformity with the fascist movement despite the Ras toying with the idea of deposing Mussolini as the leader of fascism and replacing him with the nationalist D'Annunzio who two years earlier had occupied Fiume along with 100,000 other nationalists consisting primarily of ex-soldiers.
The squads were identified by their blackshirts, a motif which ultimately coined the name Blackshirts and became the inspiration for Adolf Hitler's S.A. in the Third Reich.