The Right was opposed by the more progressive Historical Left, which overthrew Marco Minghetti's government during the so-called Parliamentary Revolution of 1876, which brought Agostino Depretis to become Prime Minister.

This phenomenon, known in Italian as trasformismo (roughly translatable in English as transformism—Prime Minister Giovanni Giolitti was depicted as a chameleon in a satirical newspaper), effectively removed political differences in Parliament, which was dominated by an undistinguished liberal bloc with a landslide majority until after World War I.

[6] This alliance governed against two smaller opposition, namely the Clericals composed by some Vatican-oriented politicians and The Extreme formed by the socialist faction which represented a real left in a present-day concept.

[8][9] A left liberal[8] with strong ethical concerns,[10] Giolitti's periods in office were notable for the passage of a wide range of progressive social reforms which improved the living standards of ordinary Italians, together with the enactment of several policies of government intervention.

In 1917, a member of the party's left-wing, Vittorio Emanuele Orlando, became Prime Minister and during his government Italy defeated Austria, earning him the title Premier of Victory.

Albeit banned by Benito Mussolini in 1925, many old Liberal politicians were given prestigious yet not influential political posts such as seats in the Senate, which was stripped of any real power by Fascist reforms.