 Henceforth, the UDSR associated itself with the Radical Party, who had been in government during most of the Third Republic, in the Rally of the Republican Lefts ("Rassemblement des gauches républicaines" or RGR), which presented itself as an alternative to the "tripartisme" alliance between the SFIO, the MRP and the French Communist Party (PCF).Following the May 1947 crisis during which Maurice Thorez, Communist vice-premier, and four other PCF ministers left Paul Ramadier's government, the UDSR took part in the Third Force coalition which gathered the centre-left and centre-right parties to face with the oppositions of the PCF on the one hand, and of the RPF on the other.It remained throughout the Fourth Republic a minor centrist political party which participated to the governments.