Maybe some legality in their parlimentary structure.
That is an idea, we should add some clause to our election laws for an automatic postponement for a fixed time period if some foreign force trys this kind of terror tactic to influence our elections!!
Spain is going to have buyers' remorse. I sense that. But without a mechanism to postpone a scheduled election, I don't think there's much choice. Such a law would have to be carefully written and until 9/11 it was totally unneeded.