The real issue
As I pointed out in almost every post on this subject back when it was a bigger issue, it's irrelevant what the Spanish voters thought about the effect of the attack on their votes, or the U.S. pundits, or any of us.
What matters is that a terrorist group blew up a train in order to change the outcome of an election, and they now firmly believe that it worked.
That's where we are, and that's the problem.