The party was declared illegal by the Mandatory authority at first, but the ban was relaxed under the French Front Populaire government, and again in 1941.

The party took a new option of collaboration with the nationalist movement and playing down its socialist themes in 1936, in accordance with the 7th World Congress of the Comintern in 1935.

During the early 1970s, the LCP established a well-trained militia, the Popular Guard, of some 5,000 armed men which participated actively in the fighting at the start of the Lebanese Civil War.

[10] In 1987, together with the Druze Progressive Socialist Party, the LCP fought a week-long battle against the Shi'a militants of the Amal in West Beirut, a conflict that was stopped by Syrian troops.

Also in 1987, the LCP held its Fifth Party Congress and was about to oust George Hawi, its Greek Orthodox leader, in favor of Karim Mroue, a Shi'a, as secretary general.

Hawi, who had been a rising opponent of the party's complete dependence on the Soviet Union, was reportedly unpopular for his idealism and unwillingness to compromise his ideology.

Two back-to-back congresses saw the exit of Hawi, Mroue and other prominent leaders of the party, which left it in a major crisis.

Hawi returned to the party as head of its national council (formerly the central committee), but later abdicated in the 1998 8th congress, which saw the second election of Dahrouj as secretary general.

[16] and less than one month after Samir Kassir, a left-wing Lebanese journalist and political figure, was assassinated in another car blast.

[20] In a formal statement, the LCP commented that "the 2009 elections widened the gap already existing because of the sectarian system,"[21] and, while expressing dismay at its electoral showing, analyzed and attempted to justify the party's performance.

This structure gives the party a national presence, but at the same time weakens its representation in the local and central governmental bodies including municipalities and parliament.