The Democratic and Socialist Union of the Resistance (French: Union démocratique et socialiste de la Résistance, UDSR) was a French political party founded after the liberation of France from German occupation, mainly active during the Fourth Republic (1947–58).
Its ideology was vague, including a broad diversity of different political convictions,[2] and it was variously described as left-wing, centrist, and even conservative.
It remained, throughout the Fourth Republic, a minor centrist political party, though it participated in various governments.
In 1956 the UDSR participated in the centre-left Republican Front coalition, headed by Pierre Mendès-France, which won the legislative election.
However, two years later, the UDSR imploded; indeed, Pleven and the party’s conservative wing approved Charles de Gaulle's comeback during the May 1958 crisis, in the midst of the Algerian War and threats of a coup d'état, and the institutions of the Fifth Republic, unlike Mitterrand, who called the new Constitution a "permanent coup d'état."