Led by Robert Fabre during the 1970s, the party was the third partner of the Union of the Left. Nevertheless, its electoral influence did not compare with those of its two allies, which competed for the leadership over the left. Robert Fabre sought to attract left-wing Gaullists to the party and gradually became close to President Valéry Giscard d'Estaing, who nominated him as Mediator of the Republic in 1978. He and his followers were excluded from the party by those who strongly supported the alliance with the PS.