[3][4] After the failed assassination attempt on the fascist prime minister Benito Mussolini in September 1926, the PCdI was outlawed and the publication of l'Unità suppressed.

When Mussolini was forced to resign on 25 July 1943 Li Causi stayed in the penal colony on the island of Ventotene, 40 kilometres to the east of Ponza.

[6] By this time the PCdI had been renamed as the Italian Communist Party (Partito Comunista Italiano; PCI), and shortly thereafter Li Causi was made the party's representative on the National Liberation Committee for Upper Italy in Milan, where he was active in producing l'Unità clandestinely and in organising the resistance.

Li Causi became the main rival of separatist leader Finocchiaro Aprile and the most consistent enemy of separatism.

Vizzini had agreed to permit the meeting and assured them there would be no trouble as long as local issues, land problems, the large estates, or the Mafia were not addressed.

When Li Causi started speaking about how the peasants were being deceived by "a powerful leaseholder" – a thinly disguised reference to Vizzini – the Mafia boss shouted: "It's a lie".

On 20–21 April 1947 the Blocco del popolo – a coalition of the Communist and Socialist parties – achieved a surprising result in Sicily's regional elections, winning a plurality of seats with 30.4% of the vote, while the (Christian Democracy) got 20.5% and the Common Man-Monarchist bloc came third with 14.8%.

Commenting on the success of the left-wing alliance, Li Causi said: For the Communist Party, there is no question of world revolution, but of feeding and democratising the people.

While the attack was officially attributed to Salvatore Giuliano, bandit and former separatist leader, the Mafia was suspected of involvement in the massacre.

The Minister of the Interior, the Christian Democrat Mario Scelba, reported to Parliament the next day that so far as the police could determine, the Portella della Ginestra shooting was non-political.

[6][16] Li Causi disagreed and claimed that the Mafia had perpetrated the attack, in cahoots with the large landowners, monarchists and the rightist Common Man's Front.

On 30 May 1947, the Christian Democrat Giuseppe Alessi was sworn in as President of the Sicilian region with the support of right-wing parties, while De Gasperi announced his new centrist government, from which the left was excluded for the first time since 1944.

"[19][20] At the trial for the Portella della Ginestra massacre, Gaspare Pisciotta said: "Those who have made promises to us are called Bernardo Mattarella, Prince Alliata, the monarchist MP Marchesano and also Signor Scelba, Minister for Home Affairs ... it was Marchesano, Prince Alliata and Bernardo Mattarella who ordered the massacre of Portella di Ginestra.

However, the MPs Mattarella, Alliata and Marchesano were declared innocent by the Court of Appeal of Palermo, at a trial which dealt with their alleged role in the event.

[22]Although Li Causi was a prominent Communist leader, his career was thwarted by party secretary Palmiro Togliatti.

Togliatti did not hesitate to replace Li Causi as regional secretary of the Party in the late 1950s, at a time when the Mafia increased its rule in rural areas as well as cities.

He also accused another Christian Democrat politician, Vito Ciancimino, of being the centre of a web of business and Mafia in Palermo administered by the DC.