The Madrid bombing (900 injured, and at least 197 dead as of last count), to be blunt, horrified me. Now, though, the question of "who did it" looms large. Instead of these bombings being being seen as clearly the work of Basque nationalists (as people had thought on Thursday), the question is now open as to who's responsible. It may be ETA (the chemical signature of the explosives corresponds with ETA) but it may well not be (the nature of the attack doesn't fit the ETA's profile).
A group affiliated with Al Qaeda claimed responsibility, but they're not credible; they also claimed responsibility for the blackout last year.
So, there are two possibilities here. First, ETA did it, which implies that the old style of attacks is dead. This doesn't necessarily mean that ETA is affiliated with Al Qaeda, although it does imply it; it may be that ETA is consciously attempting to mimic Al Qaeda. The CNN article says that they "have different goals" because the nationalism of ETA doesn't correspond with the Islamic theocratic goals of Al Qaeda, but that is really unimportant; terrorist organizations have made these pragmatic sorts of linkages for a very long time. It may well have been a response to the American War on Terror, too; a sort of "if we don't hang together we will surely hang seperately" logic would be logical in light of the war. It may also have something to do with the Chechnya conflict, as the Chechans have fairly successfully blended together Islamic fundamentalism and nationalism in ways that have (to some extent) eluded even the Arabs.
Second, Al Qaeda did it. This doesn't mean the ETA didn't have some involvement, but that Al Qaeda was the leading party. If that's the case, then the "revenge for aiding the U.S. in Iraq" scenario seems credible. The biggest problem with that scenario is that Al Qaeda didn't really have much to do with Saddam, but that doesn't really matter here, as Al Qaeda is certainly interested in the fate of Iraq now. Besides, I doubt an Al Qaeda attack in Spain would be aimed at Spanish eyes and Spanish ears- it would be aimed at potential allies as proof of Al Qaeda's remaining strength and at potential foes as an object lesson on the price of assisting the U.S. It also will create real tension and conflict in Europe, which I'm sure Osama wants; he's after a world war that Europe (until now) seemed bound and determined not to fight. Europe's significant Muslim minorities could be a powderkeg if Europe is seen as fully signing on to the United States' so-called "crusade"; the Europeans know that, and I'm sure Osama does too.
Right now, the most important job is figuring out who is responsible, so that the Spanish (and the world) know which of these scenarios they're dealing with.