Leandro N. Alem was elected president and leaders were drawn from all tendencies within the anti-government movement, including Francisco A. Barroetaveña, José Manuel Estrada, Pedro Goyena, Aristóbulo del Valle, Bernardo de Irigoyen, Juan B. Justo, Lisandro de la Torre, and influential ex-president and general Bartolomé Mitre.

The same year, supporters of the Civic Union, led by Leandro Alem and Bartolomé Mitre, instigated the Revolution of the Park, an armed uprising that ousted president Juárez Celman and replaced him with vice president Carlos Pellegrini.

The Civic Union established a presidential ticket with Bartolomé Mitre and Bernardo de Irigoyen.

After learning of the arrangement on April 16, Leandro Alem opposed it emphatically, splitting the Civic Union and forcing Mitre to abandon his candidacy.

On June 26, 1891, Alem's supporters formally founded the Radical Civic Union.