The idea of a national constitution for Spain arose from the Declaration of the Rights of Man and of the Citizen initiated as a result of the French Revolution
The earliest document recognized as such was La Pepa passed in 1812 as a result of the Peninsular War (1807–1814), which was a military conflict between the First French Empire and the allied powers of the Spanish Empire, the United Kingdom of Great Britain and Ireland and the Kingdom of Portugal for control of the Iberian Peninsula during the Napoleonic Wars.
During the Francoist State, there were many attempts to create stable institutions that did not (at least directly) emanate from Fransisco Franco as they did in the post-war period. The Fundamental Laws of the Realm (Spanish: Leyes Fundamentales del Reino) were a constitution in parts enacted through nearly 20 years starting in the 1950s. They established the very institutions that would later, under Juan Carlos I and Prime Minister Adolfo Suárez, commit "constitutional suicide" and pass the Political Reform Act, starting the Spanish transition to democracy. Most of those Laws theoretically provided for a quite free state, but ultimately the power of the Caudillo was supreme.
Finally, the constitution in force is similar to the (unwritten) British democratic monarchy model, but the Catalan self-determination referendum, 2014 has provoked calls for an entirely democratic federal republican model. Below there is a comprehensive table, but this is an overview:
|Name||In force||Form of government||Democracy||Repealed||Observations|
|1808–1814||Constitutional monarchy||Bicameral parliament with semi-elective lower house.||Peninsular War lost by Joseph I.||Not recognized by the Spanish patriots during the war. Most of its contents were to be enacted through the 1810s, so it did not actually work.|
|Constitution of 1812||1812–1814
|Constitutional monarchy||Elected parliament.||Ferdinand VII reinstated absolutism in 1814 and again in 1823. Superseded in 1837.||The Crown was granted wide-ranging veto powers, which Ferdinand VII used to prevent the liberal governments from functioning.|
|Royal Statute of 1834
|1834–1836||Constitutional monarchy||Bicameral parliament with elected lower house and appointed Senate.||Regent forced to reinstate the 1812 Constitution after a military pronunciamiento.||Granted by Maria Christina in order to get support from the liberals in the First Carlist War.|
|Constitution of 1837||1837–1845||Constitutional monarchy||Superseded.||Partially suspended by Baldomero Espartero to rule by decree between 1840 and 1843.|
|Constitution of 1845||1845–1869||Constitutional monarchy||Parliament elected by censitary suffrage.||Isabella II and her Government overthrown in the Glorious Revolution of 1868.||Doctrinaire attempt to exploit the plots against the young Isabella and the Regency in order to reinforce the monarchy|
|Constitution of 1856||Not enacted||Constitutional monarchy||Parliament elected by censitary suffrage.||Scrapped by the new government.||Passed by the Parliament but not enacted by Isabella II as moderate liberals returned to power.|
|Constitution of 1869||1869–1876||Constitutional monarchy||Parliament elected by universal male suffrage.||Republic declared by the Cortes after the abdication of Amadeo I.||An interim compromise between royalist conservatives and republican progressives|
|Constitution of 1873||Not enacted||Federal republic||Unicameral parliament elected by universal male suffrage.||Arsenio Martínez Campos led a successful pronunciamiento restoring the Bourbon monarchy.||Republic collapsed before even passing the Constitution, mainly due to wide disagreement over the federalism vs centralism issue.|
|Constitution of 1876||1876–1931||Constitutional monarchy||Parliament elected, firstly by censitary, then universal male suffrage from the 1890s.||Republic instated after Alphonse XIII fled Spain.||While theoretically democratic, elections were routinely rigged by the governing party, and in practice power was shared by two alternating parties (the turno system). During Primo de Rivera's dictatorship (1923–1930) many of its articles were suspended in a de facto dictatorship.|
|Constitution of 1931||1931–1939||Parliamentary republic||Unicameral parliament, firstly with universal male suffrage, then female suffrage from 1933.||Civil War lost by the Republican side.||During the Civil War (1936–1939) it was abolished by the Nationalists and widely disregarded in the Republican zone.|
|Fundamental Laws of the Realm||1938–1978||Authoritarian dictatorship||Partially elected unicameral parliament with little powers of its own.||Superseded when Parliament adopted the Constitution of 1978.||A set of laws enacted by the caudillo Francisco Franco in order to shape his political regime and adapt it to changes. The individual laws passed under Franco are: Fuero del Trabajo (1938), Ley Constitutiva de las Cortes (1942), Fuero de los Españoles (1945), Ley del Referéndum Nacional (1945), Ley de Sucesión en la Jefatura del Estado (1945), Ley de Principios del Movimiento Nacional (1958), and Ley Orgánica del Estado (1967).
The Law for Political Reform (Ley de Reforma Política) of 1977, last of the Fundamental Laws and passed after Franco's death, started the Spanish transition to democracy.
|Constitution of 1978||1978–present||Constitutional monarchy||Parliamentary democracy with bicameral, elective parliament.||Currently in force, though talks for reform are common in Spanish politics.||First in Spanish constitutional history not to grant any emergency power (i.e. sacking the PM, dissolving the Cortes) to the Head of State.|