Now that Spain is considering a pull-out from Iraq, the time is right for Islamicists to strike. A single attack on Spanish forces in Iraq would push the new leadership to consider an immediate withdrawl. Multiple attacks over the next few days would virtually ensure it.
Time for all allies with troops there to consider the best response before they are targeted. Britain and Italy are probably next in line. An attack in Poland would not get the response desired; Poles don’t suffer fools gladly.
Update: Tacitus has some historical info on the desire of al-Qaeda to retake Andalusia. And TNR says the new Spanish leadership need to renege on a campaign promise.