This chapter examines the motivations of the Parti Socialiste (PS), principal mover in the strategy, and those of its partners. The plural-left strategy reflected PS's views about the left-party sub-system. The chapter also examines what the plural left implied in terms of day-to-day relations between its components, especially in the light of recent government experience. The plural-left experiment had clearly had consequences for the party system, mostly for the left sub-system, though also for the system as a whole. Noël Mamère's pragmatic campaign rescued them from the electoral consequences of undiluted radicalism and saved their election expenses. The plural left sustained a viable social-democratic government up to the 2002 elections. The success of the plural left brought out a constant of the French party system ever since it first became recognisable in the late nineteenth century.