Over the question of Basque independence, in my opinion both sides have put themselves in the wrong.
The Spanish government (and indeed the French government) has put itself in the wrong by refusing to acknowledge the possibility of Basque independence. Given that there is clearly some significant support for it, they should hold a referendum in the Basque Country, and respect the result. I have no idea whether the people of the Basque Country would vote for independence, but they should have the right to be asked.
The terrorist group ETA has put itself in the wrong by killing innocent people. Although Basque nationalists have a genuine grievance, no-one is killing them, so they're not entitled to kill anyone. The members of ETA are not fighting a war, they're simply murderers, and should be dealt with accordingly. I have no sympathy with them at all.