Based mainly in Spain, it was banned in 2003, after a court ruling declared proven that the party was financing ETA with public money.

[2] Right after having been banned, Batasuna still managed to organize or support some rallies, public actions and several workplace strikes.

[3] Batasuna's ranks and support base have been represented under different names since it was first declared legal in the late 1970s with the Spanish Transition to democracy.

After having been outlawed in 2003, Batasuna's core support revamped yet again by co-opting the thus far marginal parties EHAK and Acción Nacionalista Vasca (ANV).

Batasuna was a part of the Basque National Liberation Movement which includes social organizations, trade unions, youth (Jarrai and Gazteriak, now merged in Haika and Segi), and women's groups (Egizan).

Jarrai-Haika-Segi, Gestoras pro-Amnistia, Askatasuna and other groups closely related to Batasuna were also declared illegal by different court rulings on the same charges of having collaborated with or being part of ETA.

The party was founded in April 1978 as Herri Batasuna, a coalition of leftist nationalist political groups mostly originating from Euskadiko Ezkerra initially brought together to advocate for "no" in the referendum to be held that year on the Spanish constitution.

Herri Batasuna's founding convention was held in Lekeitio, home of Santiago Brouard who was then the leader of HASI (Herriko Alderdi Sozialista Iraultzailea or Revolutionary Socialist People's Party).

Same happened in 1980 in the first elections to the Basque Parliament, in which HB stood as second political force, with 151,636 votes (16.55%) winning 11 seats.

Another well-known Herri Batasuna leader and newly elected Spanish MP, Josu Muguruza, was assassinated by right-wing extremists in November 1989 in Madrid.

Otegi, like a number of other top-ranks in Herri Batasuna, had been a member of ETA and served several years in prison for bank assault.

Amid a period of separatist kale borroka street attacks on the offices of the Basque Nationalist Party and other establishment targets, Batasuna together with the union Langile Abertzaleen Batzordeak convoked a day of protest and general strike on 9 March 2006.

A few thousands of Batasuna militants joined protests, while others blocked rail lines and roads and occupied municipal halls[6] Batasuna leader Arnaldo Otegi was ordered to appear in court to answer for the bomb attacks and disruption, but delayed his appearance repeatedly on the grounds of illness.

They called for a "unifying project for the pro-independence left" which would be aimed at creating an electoral list for regional elections to be held in Spring 2009.

While it was fairly represented in all Basque and Navarrese Spanish territories, Batasuna counted as its stronghold the province of Gipuzkoa.

Members of the Basque left consider the Spanish government's efforts against Batasuna and its successors to be part of an organized campaign targeting the social support for the independence movement.

They point to government crackdowns against the newspaper Egin, the radio station Herri Irratia and the network of pubs that were gathering places for the independentist left.

The decision automatically cut them off from the state funding received by all legal political parties with Parliament representation.

While sharing separatist aims with Batasuna, Aralar rejected political violence and ETA's assassinations and therefore remains a legal party.

This time, the Spanish Supreme Court could make a quick assessment of ANV's municipal candidates, which resulted in roughly half of them being banned (because the candidates included people who had previously run for the illegal Herri Batasuna or Batasuna) while the other half was ruled lawful and could participate in the elections to be held shortly after the ruling.

Then, in September 2008 the full legal inquiry on the party was finalized, ruling that ANV as a whole was illegal, due to ties with Batasuna-ETA.

In October 2008, demonstrations were held in Bilbao to protest a Supreme Court decision the month before to ban ANV and EHAK, because of their ties to Batasuna.

[23] Batasuna has a minor presence in the Basque French country, where it runs elections as a civic organization,[24] not like a political party.

[citation needed] In September 2008, 14 people were detained by the French police, 10 of whom were from the French-wing of the party (including their spokesman Xabi Larralde), and charged with links to ETA.