The right-wing People's Alliance (AP), led into the election by former Francoist minister Manuel Fraga, benefitted greatly from the UCD's losses, becoming the main opposition party to the Socialists with slightly over 100 seats and 26.4% of the vote.

[8][9][10] 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.

The prime minister had the prerogative to propose the monarch 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.

In his investiture speech as Prime Minister on 30 March, Adolfo Suárez outlined the main areas of his policy, including the constitutional development involving the implementation and structuring of the State of Autonomies.

[22] Subsequently, in April 1979, the first municipal elections since the Second Spanish Republic were held, in which UCD won in the overall vote tally, but lost control of the main urban centers to PSOE-PCE alliances.

Suárez found himself politically isolated—his party being the only one voting against the motion—and the resulting debate, broadcast live on radio and later on television with high audience shares, gave González a pretext to expose the Socialist government program and to present the PSOE as a viable alternative to the UCD.

[33][34] Growing division within UCD, with internal dissension and criticism gradually undermining the position of Suárez, also often resulted in the Prime Minister clashing with members of his own party.

This was the result of the complex amalgamation of forces of very varying ideologies—social democrats, conservatives, liberals and christian democrats—into a party that was artificially created around the figure of Adolfo Suárez for the sole purpose of ruling.

[23] The adoption of the first Statutes of Autonomy in Catalonia and the Basque Country led to the first regional elections in 1980, which gave a plurality to nationalist parties (CiU and PNV) and to disappointing results for UCD.

[35] Both Statutes were approved by the Catalan and Basque citizens through referendums with wide margins, complying with the procedure provided in article 151 of the Constitution for the "fast route" of accessing to autonomy, which allowed for an immediate assumption of full competences.

These factors combined with an increasing political isolation and alleged pressures from military sectors led to Adolfo Suárez announcing his resignation as Prime Minister and party leader on 29 January 1981.

A group of Guardia Civil members under the command of Lieutenant Colonel Antonio Tejero assaulted the Congress of Deputies, kidnapping both the legislative and executive power within.

[45] The legalization of divorce in mid-1981 met with criticism from the Catholic Church and the most conservative sectors within the UCD, which even demanded the resignation of Justice Minister Francisco Fernández Ordóñez, promoter of the law.

[52] But it also caused a rift between Calvo-Sotelo and former PM Adolfo Suárez, still a UCD MP, on the grounds that the incumbent Cabinet had not been duly informed of the possible consequences of an eventual Spanish entry into NATO, as well as the haste and rush with which the integration process was being carried out.

However, voters' weariness with the UCD's internal crisis and its management of the country resulted in a surprise win for the right-wing People's Alliance on an extremely low turnout (46.3%).

[60] Concurrently, the UCD's continuous splits in the Congress (with its parliamentary group reduced to 150 out of 350) had, by the summer of 1982, deprived the party of a workable majority to govern until the end of the legislature in 1983,[48] causing Calvo-Sotelo to announce the Cortes' dissolution and the call of a snap election for 28 October before the Parliament's reopening in September.

[61][62] Bill proposals such as the Statutes of Autonomy of Madrid, the Balearic Islands, Castile and León and Extremadura or the 1983 budget, scheduled to be approved throughout the autumn, had to be delayed until after the election as a result.

[63][64] Adolfo Suárez, himself the UCD's founder, staged one of the most remarkable splits by founding the centrist Democratic and Social Centre (CDS) and announcing his intention to run on its own in the next general election.

[66] Had the Cortes reopened in September after the holidays as it was initially scheduled, the UCD parliamentary group in the Congress would have been down to 124, even less than a hypothetical sum of the PSOE and PAD parties (128 seats).

Causes of ineligibility were imposed on the president and members of the Constitutional Court, the Supreme Court, the Council of State and the Court of Auditors; the Ombudsman; high-ranking members—undersecretaries, secretaries-general, directors-general and chiefs of staff—of the General State Administration, government delegations, the Social Security and other government agencies; judges and public prosecutors in active service; Armed Forces and police corps personnel in active service; members of electoral commissions; and the chairs of national trade unions; as well as a number of territorial-level officers in the aforementioned government bodies and institutions being barred from running, during their tenure of office, in constituencies within the whole or part of their respective area of jurisdiction.

Fernández Ordóñez' PAD had already reached an agreement by the spring of 1982 to run under the PSOE banner,[71][72] while talks for an eventual AP–PDP coalition were underway already before the Cortes' dissolution, being confirmed in early September.

[91][97] The PSOE also relied in a strong personalization around the figure of Felipe González, appealing to ethics and messages of hope as drivers of the political change, but also to show an image of party unity in contrast to the UCD's internal infighting of the previous years.

[98] Among the PSOE election pledges were the creation of 800,000 employments, the nationalization of banks in a critical economic situation and the decrease of retirement age from 69 to 64, as well as to establish the maximum working time at 40-hour week.

[104] After its success in the 1981 Galician and 1982 Andalusian regional elections, all opinion polls pointed to AP becoming the main Spanish opposition party, but at a great distance from the PSOE.

The Spanish Socialist Workers' Party (PSOE) swept the popular vote in nearly all regions of the country—only AP and PNV wins in Galicia and the Basque Country denied them a clean sweep of the entire national territory.

Congress Speaker Gregorio Peces-Barba (PSOE), in an uncommon gesture, did not cast a ballot and maintained strict neutrality, as his party's lopsized majority all but guaranteed González's election.

Furthermore, the exceptionally high turnout (80%) was seen as a strong endorsement by the Spanish people on the democratic system, and the political earthquake resulting from the election was deemed as the Spaniards' desire to break up with the past and to look into the future, rallying behind the PSOE and the "for change" premises it had campaigned for.

The UCD, the political party which had led the country into the transition from Francisco Franco's dictatorship into a fledgling democracy, was not only ousted from power, but almost entirely decimated in the election.

As a result, the UCD, which had been in office since its inception in 1977 until December 1982, effectively ceased to exist as in February 1983, when its leadership decided to dissolve the party as it was unable to cope with the mounting debts.

For the next decade, the Socialists would dominate Spanish politics with no other party having a realistic chance of forming government, leading some commentators to suggest that Spain had moved to a dominant-party system.