The debate about the broad front is fought between names, primaries, and acronyms, but it also has a translation in seats. With the same votes, grouping Sumar, Podemos, and the territorial forces included in this analysis raises their representation from 25 to 39 deputies. Of the fourteen they recover, eight come from PP and Vox and six from PSOE.
That is the result of the provincial exercise of DEMOCRAT: unity improves the joint representation of the space, but not all the recovered deputies change blocks. PP and Vox go from 197 to 189, still above the 176 of the absolute majority.
The scope of the alliance matters. This calculation incorporates ERC, EH Bildu, BNG, and Adelante Andalucía, in addition to the space of Sumar and Podemos. Gathering only these last two candidacies produces a different and smaller effect. They are different coalitions and must be measured as such.
One, two, or three: which candidacies are being compared
The negotiation remains open. Ada Colau has conditioned her willingness to lead the Broad Front on expanding the project to more forces, including Podemos. Irene Montero maintains the demand for open primaries. None of these positions confirms an agreement with all the territorial parties.
One of the hypotheses circulating proposes two alliances: Sumar, IU, Más Madrid, and Comuns on one side; Podemos with ERC, EH Bildu, BNG, and Adelante on the other. The analysis takes that configuration as a possibility and compares it with the integration of all the considered forces and with their separation.
| Configuration | Composition |
|---|---|
| A common list | The space of Sumar, Podemos, and the analyzed territorial forces share a ballot in each constituency. |
| Two candidacies | Sumar and its space on one side; Podemos with ERC, EH Bildu, BNG, or Adelante in their respective territories on the other. |
| Up to three candidacies | Sumar, Podemos, and the corresponding territorial force run separately. Where there is no modeled third force, there are two left. |
These are electoral hypotheses. IU, Más Madrid, and Comuns are included in the space of Sumar: no additional percentages are assigned to them. Other parties, such as Junts, PNV, or CUP, remain outside the compared alliances. "Up to three" does not mean three state lists present in all provinces.
The unit is measured where the deputies are distributed: in each constituency. ERC does not provide votes outside of Catalonia, nor does BNG outside of Galicia. It is also not assumed that a territorial alliance adds new support by presenting itself with a shared brand.
Where the votes come from: an identified survey and the map of 23J
The starting point is the October barometer from 40dB for EL PAÍS and SER, published on October 5. Its estimate places the PP at 31.6%, the PSOE at 27.4%, Vox at 18.4%, Sumar at 5.6%, Podemos at 2.7%, and SALF at 2%. The rest of the candidacies and the blank make up 12.3%.
DEMÓCRATA distributes those figures by provinces through an adjustment based on the final results of 23J. For the candidacies of the rest, their relative proportions from 2023 are maintained. Therefore, their support within the calculation are territorial assumptions, not individual estimates published now by 40dB.
The exercise allows isolating the effect of the lists: between one configuration and another, no vote changes. What changes is the candidacy to which it is added. No bonuses for leadership are incorporated, nor is it assumed that a coalition attracts abstainers.
The common list gains fourteen seats; PP and Vox lose eight
| Configuration | PP | PSOE | Vox | Analyzed space | Other forces | PP + Vox |
|---|---|---|---|---|---|---|
| A common list | 125 | 104 | 64 | 39 | 18 | 189 |
| Two candidacies | 132 | 109 | 65 | 26 | 18 | 197 |
| Up to three candidacies | 132 | 110 | 65 | 25 | 18 | 197 |
Source: DEMÓCRATA model. "Analyzed space" always includes the space of Sumar, Podemos, ERC, EH Bildu, BNG, and Adelante Andalucía. The territorial forces only contribute the votes assigned in their constituencies. All votes are maintained between configurations. Each row sums 350 deputies, excluding the subtotal column PP + Vox. The seats are self-calculations, not a projection published by 40dB.
With up to three candidacies, the analyzed space sums 25 representatives: six from Sumar, two from Podemos, and seventeen from the considered territorial forces. The PP obtains 132, the PSOE 110, and Vox 65.
With a common ballot, that space reaches 39. The PP drops to 125; the PSOE to 104; and Vox to 64. The improvement of fourteen deputies is distributed as follows: seven come from the PP, six from the PSOE, and one from Vox.
The sum of the PSOE and the analyzed forces goes from 135 to 143. To measure if the balance between blocks changes, that joint gain of eight is important, in addition to the increase in representation of the unitary candidacy.
The model locates the recoveries in fourteen constituencies, among them Alicante, Barcelona, Bizkaia, A Coruña, Navarra, Málaga, and Valencia. The sum works both where two candidacies compete for the last deputy and where one of them is left without representation.
Two alliances do not produce the same result as a common ballot
In the configuration of two candidacies, the Sumar space maintains six deputies and the alliance of Podemos with the territorial forces gathers twenty. They are 26 in total: one more than with the separation, but thirteen less than with the common candidacy.
This additional deputy comes from the PSOE, which goes from 110 to 109. PP and Vox retain their 197. In this assumption, therefore, the partial agreement redistributes representation within the left without reducing the sum of the right.
This does not measure the electoral appeal of Colau, Rufián, Montero, or any other leader. An alliance could mobilize support that the calculation keeps still, or lose voters who would not accept their new partners. The data used do not allow assigning in advance a premium or a punishment for those names.
It is also advisable to distinguish between electoral alliance and parliamentary coordination. To achieve the calculated effect, the votes must count for the same candidacy within each constituency. Sharing events, messages, or a subsequent strategy in Congress does not equate to adding ballots in the counting.
Adelante Andalucía: the missing data to complete the portrait
The vote of Adelante included in the calculation comes from its candidacy for Congress in 2023, located in Cádiz, and from the adjustment applied to the forces of the rest. It does not reproduce its subsequent autonomous result nor estimate how much it would obtain if it ran in a general election with a different implantation.
Directly transferring a percentage from the Andalusian elections and subtracting it from the PSOE would alter two things at once: the candidacies and the votes. To measure only the effect of the lists, this exercise avoids that transfer without evidence.
The lack of a self-estimate for general elections limits what can be concluded about Adelante. Its presence is contemplated, but the model does not intend to measure a possible growth of that formation compared to 2023.
The test of 23J: fragmenting also benefits the PSOE
The historical contrast allows observing the mechanism with real votes. In 2023, Sumar ran with Podemos integrated and obtained 31 deputies. The PP achieved 137, the PSOE 121, and Vox 33. PP and Vox totaled 170.
If the vote of that candidacy is divided into two lists, in a uniform proportion of 75.61% and 24.39% by province, its joint representation drops from 31 to 18 deputies. The other votes remain intact.
| Configuration | PP | PSOE | Vox | Sumar + Podemos | Other forces | PP + Vox |
|---|---|---|---|---|---|---|
| Official result of 2023 | 137 | 121 | 33 | 31 | 28 | 170 |
| Hypothetical division of Sumar | 141 | 129 | 33 | 18 | 29 | 174 |
Source: JEC and calculation of DEMÓCRATA. The vote of Sumar is divided into two candidacies in a proportion of 9.3/3, equivalent to 75.61% and 24.39%. The other votes and the provincial magnitudes of 2023 are preserved. This historical test only affects Sumar: it does not integrate territorial forces. Each row sums 350, excluding the subtotal PP + Vox.
The PSOE gains eight deputies, the PP four, and the PNV one. Vox maintains its 33. PP and Vox reach 174: four more than at the polls, but still two less than the absolute majority.
The result depends on that specific territorial division. It does not demonstrate that any separation would have produced exactly those seats nor reconstructs how citizens would have reacted to two candidacies.
What the calculation checks and what depends on the assumptions
The program first reproduces the 350 official deputies from 23J, province by province. For the current scenario, it uses the distribution from the 2026 call, with 38 deputies in Madrid and eight in Cádiz.
It applies D'Hondt and the 3% barrier of valid votes from each province; in Ceuta and Melilla, the most voted candidacy wins.
The adjustment preserves the weight of each province in the valid votes of 2023. Sumar and Podemos start from the territorial profile of their joint candidacy; SALF is initially distributed with the same percentage in all constituencies.
For Vox in Santa Cruz de Tenerife, where it did not present a list for Congress in 2023, it is assumed that it now runs and its initial profile is built with the PP-Vox relationship from Las Palmas. It is a decision of the model.
All configurations sum 350 deputies. The common condition is that the alliances preserve the votes of their members intact. The model checks the performance of those supports, not the political viability of the agreements nor their ability to attract new voters.
The final scenario: one, two, or three candidacies with 70% participation
The last test incorporates differential mobilization. It uses the certainty of voting declared at 40dB.: 67.6% of those who remember having voted for the PP are completely sure of participating, compared to 65.4% of Vox, 63.8% of Sumar, and 62.5% of the PSOE.
The reference for participation is set, as a supposition, at 67% and is raised to 70%. This is not a starting rate published by the polling agency. The model transfers those profiles of voting recall to the current electorates and increases the probability of participation among the least certain.
Podemos is assigned the Sumar profile of 2023, a candidacy in which it was integrated; for SALF and the rest, the general average is used. These equivalences are additional assumptions. Without the individual crossover between probability of voting and current intention, this section should be read as an exploratory extension.
The adjustment leaves the PP at 31.4%, the PSOE at 27.5%, and Vox at 18.3%. Sumar retains approximately 5.6% and Podemos 2.7%. With those same votes, the three configurations are repeated.
| Configuration | PP | PSOE | Vox | Analyzed space | Other forces | PP + Vox |
|---|---|---|---|---|---|---|
| A common list | 124 | 104 | 63 | 40 | 19 | 187 |
| Two candidacies | 130 | 109 | 65 | 27 | 19 | 195 |
| Up to three candidacies | 130 | 110 | 65 | 26 | 19 | 195 |
Source: conditioned model of DEMÓCRATA. The analyzed space includes Sumar and its members, Podemos, ERC, EH Bildu, BNG, and Adelante Andalucía. The reference participation of 67% is a supposition, not a forecast from 40dB. Certainty profiles by voting recall are transferred to the current electorates. Each row retains the same votes and totals 350 deputies, excluding the PP + Vox column. It is not an empirical estimate of the effect of reaching 70%.
With a common list, the analyzed forces reach 40 deputies, compared to 27 with two candidacies and 26 with up to three. The difference between unity and separation is again fourteen seats: six from the PP, six from the PSOE, and two from Vox.
PP and Vox go from 195 to 187. Unity takes away eight representatives, but keeps their total eleven above the absolute majority. With two candidacies, they retain the same 195 as with complete separation.
By varying the reference participation between 66% and 68%, while maintaining the destination at 70%, the common list obtains 39 or 40 seats and PP and Vox sum 187 or 188. With the separation, the right remains at 195 or 196. These are limited checks of the model, not confidence intervals.
The negotiation can reduce the cost of competing for the same votes. In the calculated scenarios, that savings is not enough to change the majority. To go further, it would also be necessary for the response of voters to the candidacies to change, something that the sum of ballots cannot guarantee.