[3] The goal of the platform was to "right" the course of the perceived drift of CatComú towards "the vices of traditional parties", were very critical of the role of Initiative for Catalonia Greens (ICV) within the party, and accused CatComú's leader Ada Colau of having "abandoned sovereigntism" and of "disbanding Xavier Domènech's team", after the latter's resigned as Podemos regional secretary-general and Catalan deputy.

[3][4][5] CatComú's leadership would criticize Alamany for "poor transparency" as well as the platform's establishment not being done according to internal party procedures.

[6][7] Sobiranistes was formally registered as a party on 21 February 2019,[8][9] with Alamany and Nuet breaking up from Catalunya en Comú,[1][10] and subsequently entering coalition talks with Republican Left of Catalonia (ERC) ahead of the April 2019 Spanish general election.

[11][12] Such alliance was formalized in March under the Republican Left of Catalonia–Sovereigntists label,[13] with the agreement providing for Sobiranistes to field candidates within ERC's list for Barcelona.

[19][20] During the COVID-19 pandemic, Sobiranistes broke ERC's group discipline in several occasions by abstaining—rather than opposing—in the votings for the proroguing of the state of alarm.