I bet Spain is not attacked again for sometime. AQ can show to other countries that they too can buy peace.
The terrorists have won a great victory in Spain, more terrorists attacks on Spain would turn that victory into defeat. Unless the terrorists are really really stupid, Spain will be left alone until the US is defeated.
The auhor is quite correct, the blood of the Americans, Italians, English and Dutch that will now die is aleast partly, on their hands.
The terrorists will no doubt wish to follow up their victory with other attacks on us and our allies as quickly as they can.