So, conventional wisdom has it that ceding to terrorist demands in the face of attacks—the popular, if oversimplified, gloss being put on the results of the Spanish elections—is poor strategy: It only shows that terrorism is an effective way of getting what you want, inviting more attacks. Well, maybe.

If there are a large number of distinct groups both capable and willing to orchestrate such attacks, the success of one group could obviously spur others to follow suit. But assume for a moment that we’re only dealing with one or two such groups. It seems the terrorists might well reason as follows: Our attacks have just successfuly produced state capitulation. If we attack again soon, we demonstrate that, as so many say, it doesn’t pay to negotiate with terrorists. If capitulation buys no respite from attacks, our future attacks will be increasingly unsuccessful, as populations conclude they have nothing to gain from knuckling under to our demands. If a capitulation strategy produces no gains, in other words, then a “crackdown” strategy, even if costly, will look more attractive. So if we want to preserve the effectiveness of long-term terror tactics, we’d better give the Spanish a break for a while, at least.

Of course, the logic runs the other way too, which is the reason for the conventional wisdom: If you can credibly commit to never capitulating to terror, it’s possible that terror groups will eventually conclude that terror tactics are ineffective and abandon them. But once having capitulated, it’s not obvious that you don’t realize the short term gains suggested above. I’m sure someone has done a more formal study of the game theoretic logic here; any commenters with links to post, please fire away.