However, Charles de Gaulle, who favored a presidential system, quit the government in 1946 and henceforth remained in the opposition until his triumphal return during the May 1958 crisis. For their part, the MRP, SFIO and PCF each achieved somewhere between 20% and 30% of the votes, with approximately 150 deputies each between September 1944 and May 1947. Afterwards, the PCF and de Gaulle's Rally of the French People (RPF) became France's main parties; however, both remained in opposition, because on their own they could not muster the absolute majority needed to form a government, and an alliance between them was inconceivable. The Three-Parties Alliance was succeeded in government by the Third Force, which comprised the Democratic and Socialist Union of the Resistance (UDSR), the SFIO and the MRP, with the Gaullists and the Communists forming the opposition.