This name change marked a departure, in many aspects, from the original doctrine of the late Sabino Arana and casting itself as a broader social movement rather than simply a political party.

However, the right-wing rebels insisted on a unified Spain, making them hostile to nationalist movements in regions such as the Basque Country.

The Biscayan and Gipuzkoan branches declared support for the republic, democracy, and anti-fascism in the ensuing Spanish Civil War and were key in balancing those provinces to the Republican side.

Notwithstanding their initial ambiguous position in certain areas, the party premises and press in Álava and Navarre were closed in that month of July.

The autonomous government maintained remarkable order behind the lines in Biscay and western Gipuzkoa, and managed the coordination and provision of military resistance.

Upon occupation of territories loyal to the Republic, the rebel forces focused repression on leftists, but Basque nationalists were also targeted, facing prison, humiliation, and death in some cases.

This decision allowed the occupying rebel forces to use the industrial power of Bilbao in their war effort against the rest of Republic-aligned Spain.

With no territory or help from the Republic, the Basque Army surrendered to the Italian Corpo Truppe Volontari through the so-called Santoña Agreement.

Prison sentences and executions followed, as the rebel government of Francisco Franco ruled that separate terms of surrender could not be made between the Basques and Italians.

Lehendakari Aguirre was exiled in Belgium when Hitler's forces invaded it, thus beginning his long clandestine journey to reach the United States.

Additionally, the sole Spanish representative in the United Nations was the Basque appointee Jesús de Galíndez, until his murder in an obscure episode regarding his PhD Thesis about Dominican Republic's dictator Trujillo.

He also decided to put the large Basque exiles' network at the service of the Allied side and collaborated with the US Secretary of State and the CIA during the Cold War to fight Communism in Spanish America.

The building today is the Instituto Cervantes premises where French people can learn any of the Spanish languages, including Basque.

[38] In 1959, ETA was created by young undergraduates from the area of Bilbao (organisation EKIN) lured by Basque nationalist ideology, but increasingly disgruntled at the ineffective political action of the EAJ-PNV, largely daunted by post-war repression and scattered in exile.

In addition, the new generation resented an attempt of the EAJ-PNV to pull the strings of their movement and PNV's youth wing Euzko Gaztedi (EGI), with whom they had merged in the mid-1950s, as well as showing a more modern stance, stressing for one the language as the centre of Basqueness, instead of race.

In the 1950s and 1960s, the party looked for alliances abroad, expecting at first that the defeat of the Axis in World War II would encourage USA's support for an eventual overthrow of Franco's hold on power, which did not happen.

At the same time, the Basque Nationalist Party confirmed its stance against ETA in a period when its violent actions saw a surge and its influence in society was very apparent, especially in street protests.

Juan de Ajuriaguerra paved the way for the EAJ-PNV's comeback to Basque politics from exile, and started to negotiate their participation in the new status-quo, with special attention to a new Statute.

In the transition years after Franco's death in 1975, Xabier Arzallus came to prominence, who masterminded the so-called "Spirit of Arriaga" to accommodate the party to the new Spanish democracy.

Carlos Garaikoetxea spearheaded the new autonomous government after being elected with 38.8% of the votes and during this first term the Basque Nationalist Party held office without outside support.

During this period, the EAJ-PNV's challenges were closely associated to its position in the Basque Government: defense of the Statute, devolution of powers from Madrid, discrediting of political violence, restructuring of manufacturing industry steeped in crisis.

Since 1991, as time has eased the bitter split (helped by the fact that both Arzalluz and Garaikoetxea have gone into political retirement), both parties agreed to form an electoral coalition in a number of local elections as a means to maximise the nationalist votes, which eventually led to reunite both candidatures in a joint list again for the regional governments of Navarra and the Basque Autonomous Community in 1998.

Jeltzale in the party's Basque-language name Euzko Alderdi Jeltzalea is a word comprising two parts: JeL (the acronym for "God and the Old Laws") and -(t)zale (literally meaning "fond of").

[29] In the European Committee of the Regions, the Basque Nationalist Party sits in the Renew Europe CoR group with one full and one alternate member for the 2020-2025 mandate.