Electoral system

The Spanish Cortes Generales were envisaged as an imperfect bicameral system. The Congress of Deputies had greater legislative power than the Senate, having the ability to vote confidence in or withdraw it from a prime minister and to override Senate vetoes by an absolute majority of votes. Nonetheless, the Senate possessed a few exclusive (yet limited in number) functions—such as its role in constitutional amendment—which were not subject to the Congress' override.^[9][10] Voting for the Cortes Generales was on the basis of universal suffrage, which comprised all nationals over 18 years of age and in full enjoyment of their political rights.

For the Congress of Deputies, 348 seats were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which included blank ballots—being applied in each constituency. Seats were allocated to constituencies, corresponding to the provinces of Spain, with each being allocated an initial minimum of two seats and the remaining 248 being distributed in proportion to their populations. Ceuta and Melilla were allocated the two remaining seats, which were elected using plurality voting.^[9][11] The use of the D'Hondt method might result in a higher effective threshold, depending on the district magnitude.^[12]

As a result of the aforementioned allocation, each Congress multi-member constituency was entitled the following seats:^[13]

For the Senate, 208 seats were elected using an open list partial block voting system, with electors voting for individual candidates instead of parties. In constituencies electing four seats, electors could vote for up to three candidates; in those with two or three seats, for up to two candidates; and for one candidate in single-member districts. Each of the 47 peninsular provinces was allocated four seats, whereas for insular provinces, such as the Balearic and Canary Islands, districts were the islands themselves, with the larger—Majorca, Gran Canaria and Tenerife—being allocated three seats each, and the smaller—Menorca, Ibiza–Formentera, Fuerteventura, La Gomera, El Hierro, Lanzarote and La Palma—one each. Ceuta and Melilla elected two seats each. Additionally, autonomous communities could appoint at least one senator each and were entitled to one additional senator per each million inhabitants.^[9][11]

Election date

The term of each chamber of the Cortes Generales—the Congress and the Senate—expired four years from the date of their previous election, unless they were dissolved earlier. The election decree was required to be issued no later than the twenty-fifth day prior to the date of expiry of parliament and published on the following day in the Official State Gazette (BOE), with election day taking place on the fifty-fourth day from publication. The previous election was held on 12 March 2000, which meant that the legislature's term would expire on 12 March 2004. The election decree was required to be published in the BOE no later than 17 February 2004, with the election taking place on the fifty-fourth day from publication, setting the latest possible election date for the Cortes Generales on Sunday, 11 April 2004.^[11]

The prime minister had the prerogative to dissolve both chambers at any given time—either jointly or separately—and call a snap election, provided that no motion of no confidence was in process, no state of emergency was in force and that dissolution did not occur before one year had elapsed since the previous one. Additionally, both chambers were to be dissolved and a new election called if an investiture process failed to elect a prime minister within a two-month period from the first ballot.^[9] Barred this exception, there was no constitutional requirement for simultaneous elections for the Congress and the Senate. Still, as of 2024 there has been no precedent of separate elections taking place under the 1978 Constitution.

On 9 January 2004, it was announced that the general election would be held in March,^[14][15] with the election date being agreed with Andalusian president Manuel Chaves to make it being held concurrently with the 2004 Andalusian regional election.^[16]

The Cortes Generales were officially dissolved on 20 January 2004 after the publication of the dissolution decree in the BOE, setting the election date for 14 March and scheduling for both chambers to reconvene on 2 April.^[13]

Party slogans

Congress of Deputies

Senate