 Its president René Pleven was named president of the Council from 1951 to 1952, before being succeeded by Antoine Pinay (National Centre of Independents and Peasants, CNIP).But Pleven's leadership was eventually challenged by François Mitterrand who advocated a realignment to the Left, and took the lead in 1953.In 1956 the UDSR participated in the centre-left coalition Republican Front, headed by Pierre Mendès-France, which won the legislative election.