1987 Zaragoza municipal election

Under the 1978 Constitution, the governance of municipalities in Spain—part of the country's local government system—was centered on the figure of city councils (Spanish: ayuntamientos), local corporations with independent legal personality composed of a mayor, a government council and an elected legislative assembly.^[2] The mayor was indirectly elected by the local assembly, requiring an absolute majority; otherwise, the candidate from the most-voted party automatically became mayor (ties were resolved by drawing lots).^[3] In the case of Zaragoza, the top-tier administrative and governing body was the City Council of Zaragoza.

The term of local assemblies in Spain expired four years after the date of their previous election. The election decree was required to be issued no later than 25 days prior to the scheduled expiration date of the assemblies and published on the following day in the Official State Gazette (BOE), with election day taking place between 54 and 60 days after the decree's publication.^[4] The previous local elections were held on 8 May 1983, which meant that the chambers' terms would have expired on 8 May 1987. The election decree was required to be published in the BOE no later than 14 April 1987, setting the latest possible date for election day on 13 June 1987.

Local assemblies could not be dissolved before the expiration of their term, except in cases of mismanagement that seriously harmed the public interest and implied a breach of constitutional obligations, in which case the Council of Ministers could—optionally—decide to call a by-election.^[5]

Elections to the assemblies of local entities were officially called on 14 April 1987 with the publication of the corresponding decree in the BOE, setting election day for 10 June.^[6]

Voting for local assemblies was based on universal suffrage, comprising all Spanish nationals over 18 years of age, registered and residing in the municipality and with full political rights (provided that they had not been deprived of the right to vote by a final sentence, nor were legally incapacitated), as well as resident non-nationals whose country of origin allowed reciprocal voting by virtue of a treaty.^[7]

Local councillors were elected using the D'Hondt method and closed-list proportional voting, with a five percent-threshold of valid votes (including blank ballots) in each municipality.^[8] Each municipality was a multi-member constituency, with a number of seats based on the following scale:^[9]

The law did not provide for by-elections to fill vacant seats; instead, any vacancies arising after the proclamation of candidates and during the legislative term were filled by the next candidates on the party lists or, when required, by designated substitutes.^[10]

The electoral law allowed for parties and federations registered in the interior ministry, alliances and groupings of electors to present lists of candidates. Parties and federations intending to form an alliance were required to inform the relevant electoral commission within 10 days of the election call, whereas groupings of electors needed to secure the signature of a determined amount of the electors registered in the municipality for which they sought election, disallowing electors from signing for more than one list. In the case of Zaragoza, as its population was between 300,001 and 1,000,000, at least 5,000 signatures were required.^[11]

Below is a list of the main parties and alliances which contested the election:

Candidacy		Parties and alliances	Leading candidate		Ideology	Previous result		Gov.	Ref.
						Vote %	Seats
	PSOE	List Spanish Socialist Workers' Party (PSOE)		Antonio González Triviño	Social democracy	52.4%	18		[12] [13] [14]
	AP	List People's Alliance (AP)		Rafael Zapatero	Conservatism National conservatism	22.3% [a]	8		[1]
	PDP	List People's Democratic Party (PDP)		José Alberto García-Atance	Christian democracy				[15] [16]
	PAR	List Aragonese Party (PAR)		Emilio Eiroa	Regionalism Centrism	13.3%	4
	CAA–IU	List Communist Party of Aragon (PCE–A) Socialist Action Party (PASOC) Republican Left (IR)		José Luis Martínez Blasco	Socialism Communism	5.4% [b]	1
	CDS	List Democratic and Social Centre (CDS)		Rafael de Miguel	Centrism Liberalism	3.1%	0

The tables below list opinion polling results in reverse chronological order, showing the most recent first and using the dates when the survey fieldwork was done, as opposed to the date of publication. Where the fieldwork dates are unknown, the date of publication is given instead. The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour. If a tie ensues, this is applied to the figures with the highest percentages. The "Lead" column on the right shows the percentage-point difference between the parties with the highest percentages in a poll.

The table below lists weighted voting intention estimates. Refusals are generally excluded from the party vote percentages, while question wording and the treatment of "don't know" responses and those not intending to vote may vary between polling organisations. When available, seat projections determined by the polling organisations are displayed below (or in place of) the percentages in a smaller font; 16 seats were required for an absolute majority in the City Council of Zaragoza.

Polling firm/Commissioner	Fieldwork date	Sample size	Turnout							Lead
1987 municipal election	10 Jun 1987	—N/a	66.8	38.7 13	–	23.1 8	7.2 2	10.7 3	14.9 5	15.6
Demoscopia/El País[p 1]	22–26 May 1987	?	67	34.6 11/12	–	25.3 8/9	5.4 1	19.4 6	13.1 4	9.3
1986 general election	22 Jun 1986	—N/a	70.4	42.3 (15)	25.1 (9)	10.7 (3)	4.5 (0)	11.8 (4)	[c]	17.2
1983 municipal election	8 May 1983	—N/a	61.8	52.4 18	22.3 8	13.3 4	5.4[b] 1	3.1 0	[c]	30.1