Banning Batasuna will shift the Basque conflict into a new phase

In the 23 years that Batasuna, under various names, has operated as a legal party, it has constantly trod a fine line between stressing its independence from Eta's armed separatists and acting as the mouthpiece of those wielding the pistol and the bomb.

The party always pointedly fails to condemn Eta terror attacks – a sure sign, say opponents, that it is tarred with the same brush.

No one embodies Batasuna's ambiguity more than its leader, Arnaldo Otegi, himself a former Eta hitman. For a moment during Eta's 14-month truce, which ended in December 1999, Mr Otegi was considered as a possible Gerry Adams whose bloody credentials gave him the clout to bring the gunmen to the negotiating table.

The questions asked then were: how far is Batasuna genuinely independent from Eta? How far can we trust them? Most politicians in Madrid believe the truce was a ruse orchestrated by Eta to let its military apparatus recruit new blood. It now seems evident that a new hardline generation of youngsters swelled its ranks during the so-called truce.

There were no deaths, but street violence orchestrated by Jarrai – Batasuna's youth organisation, now renamed Segi – continued unabated. Many young Eta members detained in recent months started out chucking Molotov cocktails at policemen in the late 1990s.

Batasuna, for its part, accuses the government of tricking it during the truce. It was a one-sided ceasefire, the party says. Secret talks were leaked to the press by the government, and one of its negotiators was even picked up by police.

Batasuna attributes the increase in the number of young Eta militants ready to shoot and bomb to what it calls the disproportionate prison terms handed down to its members for street violence.

"I've been defending people who have been given 14 years for burning a cash machine," Jone Goirizelaia, Batasuna's lawyer said.

"With sentences like that, many feel they might as well take up arms. They've got nothing to lose."

Ms Goirizelaia tried fruitlessly to persuade Judge Baltazar Garzon not to suspend Batasuna while he opened a criminal investigation into its alleged links with Eta. Judge Garzon has been investigating Batasuna's convoluted inner workings for years, and believes he has established the financial and organisational links that prove the party is the creature of the armed organisation.

Judge Garzon's juridical operation and the government's political crackdown have coincided by chance. Their combined effect may shift the Basque conflict into a new stage, but a peaceful solution seems no nearer.