I haven't paid attention to Atgentinian politics for a while and ignore what's going on lately, but anyway I wouldn't say the UCR base of support is comparable to that of the Peronists. The UCR ceased to be competitive in presidential elections since Fernando de la Rúa fled in helicopter from the presidential palace. In fact, the main contenders to the Kirchners in the period between 2003 and 2015 were not UCR candidates - the old party even endorsed the peronist Roberto Lavagna in 2007. I think the UCR has been largely replaced by the PRO as the main non-peronist party, especially in Buenos Aires and the largest urban centres. However, the UCR still retains a base of support in some provinces and these local machines are its main asset within the opposition coalition. Being somewhat remarkable, by no means that base of power in the provinces threatens peronist hegemony. Currently the UCR has three provincial governors: Gustavo Valdes (Corrientes), Gerardo Morales (Jujuy) and Rodolfo Suárez (Mendoza).
Question: is the old Socialist Party completely disappeared?
They seem to be one of the component of what the poster called "Federal Peronism".
