This particular operation is either ISIS-conducted or ISIS-oriented vigilanteism; whichever it is, backing down in Syria will only embolden them. (Or rather, embolden those like them; I don't imagine that very many of the specific attackers here are going to have particularly many opportunities to do this again in the future.)
ISIS is specifically out for either world empire or apocalyptic defeat (see http://www.theatlantic.com/magazine/archive/2015/03/what-isi... ); tactical concessions will work about as well as they did with the Nazis and the Communists -- or even less well than that, since neither Naziism nor Communism believed that success was a sign that Divine Providence was smiling on them.
Which is why (in my understanding) ISIS does not do attacks on foreign soil. Their idea is to re-establish a caliphate (ei Islamic empire, which existed from around the time of Mohamed for centuries). ISIS would probably be okay with those that cannot join the jihad in Syria conducting a terrorist attack on their home turf, but would not actively plan one.
All I'm saying is I would not be surprised if this isn't specifically ISIS.
You didn't study your history, comrade! Communist orthodoxy believed in a historical inevitability that overlapped very closely with a sort of man-made Divine Providence. The Nazis had their own set of religious and spiritual motivations, their racial destiny and so on.
They differed from Abrahamic religions in the sense that they expected "victory" in this world and in their time, as opposed to vague posthumous compensations and end-of-times prophecies; but they did believe in a "greater power" manifesting itself in their successful deeds.
> backing down in Syria will only embolden them.
That's a false dichotomy. The problems in Syria won't go away with bombs, and it was manifestly stupid for Hollande to join the party willy-nilly, especially after having experienced first-hand the inefficiency of his security apparatus. What is needed is a real agreement between the real power brokers (Turkey, Saudi, Russia, Iran) to cut off the crazies for good. We need hard diplomacy, not hard policies.
> They differed from Abrahamic religions in the sense that they expected "victory" in this world and in their time, as opposed to vague posthumous compensations and end-of-times prophecies; but they did believe in a "greater power" manifesting itself in their successful deeds.
Good point; I forgot about the historical-determinist side of Communism. I'm more familiar with the Nazis, who believed in an empty, Providence-less cosmos that was more or less Lovecraftian (and who accordingly made themselves a pretty convincing Cthulhu) -- see _Black Earth: The Holocaust as History and Warning_ for the details.
> That's a false dichotomy. The problems in Syria won't go away with bombs, and it was manifestly stupid for Hollande to join the party willy-nilly, especially after having experienced first-hand the inefficiency of his security apparatus. What is needed is a real agreement between the real power brokers (Turkey, Saudi, Russia, Iran) to cut off the crazies for good. We need hard diplomacy, not hard policies.
Surely both at once wouldn't hurt. We need concerted ground action to defeat ISIS -- and in particular, we need Turkey to decide once and for all which side they're on -- but I don't think it's a bad idea to present a united front; I _do_ think that it's a bad idea to imagine that making concessions will inspire fewer lone wolves and opportunists, rather than more.