Citizens initially presented itself as a left-of-centre party that promoted social democratic and progressive liberal positions,[30] but it removed any mention of social democracy from its platform in February 2017,[31] moving closer to the political centre. By 2018, it was judged by commentators to have drifted further away from the left, as its focus shifted to competing against both the People's Party (PP) and Vox as the leading party of the Spanish right.[32][33][34][35] This was concurred by opinion polling and the research institute CIS, who also deemed the party to be right-leaning.[36][37][38]
The party initially enjoyed growing support throughout the 2010s on a regional and national level, owing to its staunch opposition to Catalan independence as well as the PP's decline in popularity under then-Prime Minister Mariano Rajoy. Entering the Congress of Deputies in 2015 in fourth place, it became the single largest party in the Parliament of Catalonia in 2017 and entered government in multiple autonomous communities. Citizens reached its electoral zenith at the April 2019 general election, where it became the third-largest party in the country and pulled ahead of the PP in several regions. This popularity did not last long: after refusing to form a coalition with the Spanish Socialist Workers' Party (PSOE),[39] that year's November snap election saw Citizens lose 47 seats and become the country's smallest national party, resulting in leader Albert Rivera's resignation and departure from politics.[40] This proved to be the first of a succession of electoral defeats that would set Citizens on the path to near-complete political collapse, with the party's decline mainly benefitting the PP and Vox.
^Bonnie N. Field; Caroline Gray (2019). "The Spanish Parliament in Context". In Jorge M. Fernandes; Cristina Leston-Bandeira (eds.). The Iberian Legislatures in Comparative Perspective. Taylor & Francis. p. 53. ISBN978-1-351-06520-7.
^Marta Fraile; Enrique Henández (2020). "Determinants of Voting Behaviour". In Diego Muro; Ignacio Lago (eds.). The Oxford Handbook of Spanish Politics. Oxford University Press. p. 383. ISBN978-0-19-882693-4. Ciudadanos...competes with the PP in the centre-right of the ideological continuum.
^"Catalexit?". The Economist. Vol. January 7th-13th. 2017. p. 19.
^Ciudadanos – Partido de la Ciudadanía. "Citizens' Ideario"(PDF). ciudadanos-cs.org (in Spanish). Archived from the original(PDF) on 22 January 2015. Retrieved 27 September 2016. Tercera, por el vacío de representación que existía en el espacio electoral de ultra-derecha no nacionalista
^Diari de Terrassa (9 April 2009). "Javier González: 'Nuestro objetivo es impulsar una tercera vía política en España". ciudadanos-cs.org (in Spanish). Retrieved 27 September 2016. Somos postnacionalistas y no queremos luchar contra un nacionalismo con otro. Vamos sin banderas, casi desnudos, abriendo camino sin fronteras desde la Constitución