Al Qaeda document:

We think the Spanish government will not stand more than two blows, or three at the most, before it will be forced to withdraw because of the public pressure on it,…
If its forces remain after these blows, the victory of the Socialist Party will be almost guaranteed — and the withdrawal of Spanish forces will be on its campaign manifesto.

This al Qaeda plan was published months before the bombings and elections that accomplished it. Which U.S. ally will the terrorists go after next? Despite the president’s appeals, I think anti-Americanism is too pervasive for any European government to make a principled stand against terrorism and survive the elections.
(More at Cox & Forkum.)