This is how the left and the right try to control the Senate: joint candidacies come into play

It is the Upper House, but, when it comes to reaching the electoral college, the importance that the voter gives to the Senate is significantly lower than that received by the Congress. This is not the case among the parties, which know what is at stake. Therefore, the dispute to gain control has opened a new negotiation avenue ahead of the general elections on November 29. The left has begun to explore joint candidacies to concentrate the vote and challenge the Popular Party for the majority of this Chamber. In parallel, PP and Vox could study a similar strategy in certain provinces if their rivals run united.

Vozpópuli publishes this Wednesday that the national leaderships of PP and Vox are exploring the possibility of presenting joint lists to the Senate in the constituencies where coordination could facilitate the obtaining of seats. According to this media, the option would be conditioned on the left closing its own unitary candidacies and would not necessarily imply a generalized agreement for the entire territory.

The left is already negotiating joint candidacies to the Senate

PSOE and the parties that make up the Broad Front met on Sunday, October 11, to study the possibility of running together for the Senate. The meeting served to open conversations, although the formations have not announced a definitive agreement nor detailed in which provinces the formula could be applied.

The socialists have acknowledged that they are studying different alternatives for the elections on November 29, with the intention of preventing the PP from maintaining its absolute majority in the Upper House. The PSOE leadership believes that the fragmentation of the progressive vote could facilitate the right obtaining more seats than it would achieve if the candidacies were coordinated.

The negotiation occurs while the Broad Front, formed by United Left, Sumar Movement, Más Madrid, and Comuns, finishes defining its structure and its lists for Congress. The possibility of sharing candidacies to the Senate opens a cooperation avenue distinct from the composition of the lists for Congress, where each organization maintains its own priorities and negotiations.

The electoral calendar adds pressure to the conversations. Friday, October 16 is the deadline to inform the Electoral Board of the intention to run in coalition. Until then, the parties must determine whether the agreement is limited to certain constituencies or if it reaches a broader territorial scope.

How the Senate is elected and why joint lists matter

The Senate is the Chamber of territorial representation and combines senators elected directly at the polls with others appointed by the autonomous parliaments. In most provinces, four senators are elected; the island constituencies, Ceuta, and Melilla have specific rules. The current total composition is 266 members.

Unlike the elections to the Congress, in which the distribution of seats is carried out through closed lists and a proportional system by constituencies, in the Senate elections, the vote is individual for each candidate. In the mainland provinces, each voter can mark up to three names, and the most voted candidates are elected until the four assigned positions are filled.

This system can favor candidacies capable of concentrating support. If several ideologically close parties present candidates separately, their votes can be split among different lists, while a coordinated candidacy can gather more support for its candidates. The alliance does not guarantee obtaining more seats, but it allows for designing a common strategy to compete for them.

Coordination also has a political component. The Senate participates in the legislative process, can veto or introduce amendments to bills —although the Congress can lift the veto under the terms provided by the Constitution— and performs specific functions in territorial matters. A broad majority allows a party or bloc to lead the Table, promote initiatives, and control the parliamentary activity of the Chamber.

The composition of the Senate is especially relevant for the renewal of the Constitutional Court. Four of its twelve magistrates are proposed by the Upper House, and the election requires a three-fifths majority. With the 266 senators that currently make up the Chamber, that proportion amounts to 160 votes. Achieving it would give the block that gathered that majority the ability to approve those proposals without needing external support, although the renewal procedure is subject to the corresponding legal requirements.

The struggle for the Senate is therefore not limited to adding seats to obtain an absolute majority. Joint candidacies can be a tool to improve the representation of each block and condition institutional decisions that require reinforced majorities. The unknown now is whether the confirmed negotiations of the left will translate into concrete agreements and whether PP and Vox will end up responding with their own electoral coordination.