The PSOE rose to 33% in voting intention in the CIS’s July barometer, widening its lead over the Partido Popular (PP) to 7.9 points amid recent corruption scandals involving prominent figures. That was a 1.7-point increase from June, following a sharp drop the previous month linked to the indictment of former president José Luis Rodríguez Zapatero and the unsealing of the “caso Leire Díez” investigation.
The Centro de Investigaciones Sociológicas (CIS), Spain’s public opinion research institute, conducted the survey from 1 to 6 July 2026, completing 4,020 interviews. The PP stood at 25.1%, down two points from June, while Vox fell 0.5 points to 15.3%. Sumar and Podemos each lost three tenths, reaching 6.1% and 2.5%, respectively. These figures estimate voting intention, not election results. The CIS measure combines respondents’ stated vote intention with party sympathy.
Fieldwork ended before later reporting on the conviction of David Sánchez, the Prime Minister’s brother, for malfeasance. The poll so records opinion during the first six days of July, before respondents could react to developments reported afterward. Its timing also coincided with the immediate aftermath of the PP-Vox agreement that secured Juanma Moreno’s investiture in Andalusia.
The period also brought heated debate over the “ley de nietos,” a provision of the Law of Democratic Memory that facilitates Spanish nationality for descendants of exiles from the Franco era. PP leader Alberto Núñez Feijóo accused the government of “engineering new voters,” while Vox called for the suspension of postal voting rights for expatriates.
These developments have added to volatility within Spain’s left-wing bloc. Sumar has remained below 7% in CIS voting-intention estimates since March, and both Sumar and Podemos lost support in the July figures. The survey captures opinion at a particular moment. Its results do not establish that individual political deals or legal controversies caused those shifts.
Later polling analysis has highlighted a wider gap between CIS estimates and private polls. An October CIS estimate, based on fieldwork ending 6 October, put the PSOE at 34%, the PP at 22.2%, Vox at 17.1% and Sumar/Frente Amplio at 6.1%. Riotimes Online’s election tracker listed the estimate but excluded it from its private-poll average, saying the CIS had placed the PSOE well ahead of private pollsters. Separately, Demócrata’s October average of 12 firms put the PP at 31.3%, the PSOE at 27.1% and Vox at 18.6%. Excluding the CIS, its figures were 32.1%, 26.5% and 18.8%, respectively. These later comparisons provide context for the July barometer, but do not change what respondents said during its fieldwork.
Mapa Electoral has also noted that the CIS’s headline “intention to vote” measure combines stated voting intention with party sympathy. Its analysis of the three general elections since 2019 found that the institute had overestimated the PSOE’s margin over the PP by between one and 6.9 points. Those historical comparisons matter when assessing polling estimates: they are snapshots, not predictions of an eventual result.
Internal tensions within the PP have also surfaced in recent months, particularly over the party’s stance on citizenship laws and absentee voting. For further context on these disputes and their effect on the party’s strategy, see this analysis of recent criticism faced by Alberto Núñez Feijóo within the PP. The disputes leave Spain’s basic parties navigating shifting alliances and public scrutiny as they contend for support.
The CIS regularly publishes barometers tracking political sentiment, and parties and analysts closely follow its findings ahead of national elections. The July figures offer a snapshot of voting intention gathered from 1 to 6 July 2026, before later developments entered the public debate.
