Txapote, 45, was found guilty of a car bombing that killed Basque regional lawmaker Fernando Buesa and his bodyguard Jorge Diez, in the northern town of Victoria on February 22, 2000.
Two others were wounded in the attack.
The sentence by three judges of the National Court, the highest judicial authority, was the first since ETA announced October 20 an end to violence in its fight for a Basque homeland.
Arrested in France in 2001, Txapote was delivered to Spanish justice in December 2007 after having been condemned to heavy sentences by the Spanish courts for a series of attacks.
In practice, jail terms in Spain are limited to a maximum 40 years.
ETA announced in a video last month that it had decided to abandon a campaign of violence after more than four decades of bombing and shooting that claimed 829 lives.
The group, which seeks to carve out a homeland in northern Spain and southwestern France, called on the Spanish and French governments to open direct dialogue over "the consequences of the conflict."
Neither France nor Spain formally responded to the call for dialogue with ETA, which is classified as a terrorist group by the European Union and the United States.
Spain`s centre-left Socialist government welcomed the declaration but said it will not soften its stance on ETA before November 20 general elections, widely expected to deliver power to the Popular Party. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
