While these movements have shared the objective of establishing a republic, during these three centuries there have surged distinct schools of thought on the form republicans would want to give to the Spanish State: unitary or federal.
Despite enjoying a wider support within the left wing political camp, there are also liberal, right-wing, conservative and nationalist parties espousing republican stances.
But Spain was in a period of profound instability: Legitimist monarchist Carlists (reactionaries and staunch defenders of the Ancien régime) had launched another war against the country's progressive direction; there was colonial unrest in Spanish Cuba via the Ten Years' War; and the moderate-liberal monarchy was met with stiff opposition from all sides, by republicans to its left, and from its right by a large part of the aristocracy and the Catholic Church; thus King Amadeo abdicated on 11 February 1873.
The complicated political situation is demonstrated by the fact that in just eleven months there were four presidents of the Republic: Estanislao Figueras, Francisco Pi y Margall, Nicolás Salmerón and Emilio Castelar.
Following the acceptance of the coup by the Captain General of Madrid, Fernando Primo de Rivera, a new government led by Antonio Cánovas del Castillo was formed putting and end to the Republic, bringing the so-called Restoration and the ascension of Alfonso XII (son of Isabella II) to the throne.
After being banished from the institutions, republicanism underwent a heap of troubles, with differences of approach becoming apparent between those followers of Pimargallian "pactist" federalism and those ready to jump into Castelar's possibilism in regard of the new conservative regime.
The bulk of Republican forces convened in August 1930 and reached an agreement, the Pact of San Sebastián, delimiting a common strategy to bring the republic, also conforming a revolutionary committee.
On 14 April 1931, two days after a round of municipal elections (understood as a plebiscite on monarchy) in which republicans won a landslide victory, Alfonso XIII fled the country, the Second Spanish Republic was proclaimed and a provisional government presided by Niceto Alcalá Zamora was formed.
The general elections of 1933 saw the emergence of José María Gil-Robles's Confederación Española de Derechas Autónomas, an umbrella organisation of various conservative and Catholic-nationalist parties.
The violent repression of the Rising, especially in Asturias, the suppression of Catalan home rule, and the arrest of numerous prominent political figures who had been uninvolved in the unrest, motived the formation of the Spanish Popular Front.
The Popular Front emerged victorious in the legislative elections of 1936, forming a government of republican parties and elevating Manuel Azaña as head of state.
Emilio Mola, leader of the uprising against the Second Republic, attempted to establish a "republican dictatorship,"[4] but in 1947 Franco declared his authoritarian reign as a regency for the monarchy, naming Juan Carlos de Borbón, grandson of the ousted Alfonso XIII, as his successor and the next king in 1969.
The anti-Francoist opposition failed in their attempts to bring about Francoist Spain's downfall, and after his death they started a process of negotiation with the government that led to the Spanish transition to democracy.
In 1977, after the first democratic general elections since the 1930s, the Spanish Republican government-in-exile, maintained since their defeat in the Civil War, dissolved itself and officially recognized the post-Francoist democracy.
[15][16] A study published on 24 June 2004 found 55% of Spaniards agreeing ("más bien de acuerdo") with the statement that "the Monarchy discussion is long ago a thing of the past.
"[17][note 1] In 2016, it was revealed that during a 1995 interview, Adolfo Suárez had confessed that he included the word 'King' in the 1977 Political Reform Act in order to avoid a referendum on republic, as secret surveys reportedly commissioned by the State did not deliver a favorable results for the monarchist option back at the time.
[20] Despite this, some surveys show the public in favour of the monarchy, and according to an August 2008 El Mundo poll, 47.9% of Spaniards would have liked to democratically elect King Juan Carlos, and 42.3% of respondents thought that the succession of his heir Prince Felipe should be put to a plebiscite.