First off, I’d like to say that I fully agree with Aznar that Batasuna is "basura". Batasuna is horrible, but not necessarily illegal. I am living in Bilbao and can see a side of this conflict that I think you should see.

1.There are some people here that see what is happening to Batasuna and think that Spain is escalating its efforts against the Basque Country and think that they should escalate their efforts against Spain (i.e. become more radical). I have heard one person here say “This is war now”.
2.The issue of illegalization has given Batasuna something new to talk about, taking the attention off of its failure to condemn the murder of a 6 year old child. Illegalization will just give ETA another reason to call the Spanish government “fascist” and attract new recruits.
3.Other groups were outlawed and new groups have popped up to take their place. By letting the group continue, you at least have your enemies consolidated and can control them to some degree.

Also, I think that the Batasuna senators don’t attend any sessions because they are abstaining from the process in protest.

Few people here thing that this will change anything, if anything it might just provoke more violence. It might feel good to do now, this but it is important to consider the long term effects of this process.

This can be an emotional subject and I think that if everyone keeps their cool we can have an interesting, respectful discussion of it.