[An4ximandros]

It'd be a joke, like everything else North Korea attempts to do outside of its own borders anywhere ever?

FTFY. Well, yeah, but you can chalk it up to it being North Korea, with all their delusions, incompetence and lies. Let's assume we're talking competent terrorist group that just happens to use North Korea for its resources and technology. We're talking about a regime just as fanatical, but somewhat less deluded.

NK might suck at a lot of things, but its concentration camps are no joke.

[Phantom Hoover]

And it's been remarkable in its long-term stability, and I see no reason ISIS would be able to recreate that given the wildly different circumstances involved.

[MP-Ryan]

Imagine if they had an actual, semi-functioning country providing staging grounds for terrorism. They would be capable of taking pot-shots at targets (military and civilian) everywhere, with much better equipment, larger recruit pool and better coordination.

They would also be carpet-bombed back to before the Stone Age.  State-sponsored terrorism only works if you have a state, with allies, and preferably a nuclear deterrent.  And even then, you don't want to be on that list - note how hard NK fights to stay off of it.  Otherwise, you might as well say "NATO air forces, here I am!"  Infrastructure we can level. Guys hiding in caves.... meh.  Not how ineffective Al Qaeda got after Afghanistan got flattened.

They could use this to force us to enact paranoid anti-terrorism measures which would be crippling by themselves, or live in fear of a terrorist attack. Letting ISIS establish a stable country would be a disaster that would very much threaten the rest of the world. Think of it as another North Korea in the middle of a strategic region, and with a penchant for sabotaging other countries. What happens to the populace is not the only concern here.

ISIS is in no way comparable to NK. If nations fall to psychological stupidity, that's their problem. ISIS can't form a stable country without losing what makes it ISIS.  They only operate now through mobility - the moment they've created any sort of infrastructure is the moment they get introduced to aerial ordinance.  Air power alone, as is being exercised right this second, is more than sufficient to keep ISIS from posing any tangible threat to other countries. And no, I don't count the odd lone self-radicalized operative already in those nations.

Also, there is a matter of Israel, which would be directly threatened if ISIS established a strong power base. Option "2" means essentially "We leave Israel to fend for itself". Which it might or might not pull off. If ISIS managed to establish themselves in Iraq and Syria, they would surely want to get rid of both a major enemy and a big thorn in many peoples' side. If they managed to win that war, we'd be looking at a second Holocaust, given the usual attitude of Islamists towards Jews.

I'm going to rebut this with as few words as possible: 6-Day War. Yom Kippur War. Every war since. Dimona.

ISIS poses no threat to Israel (virtually no state in the Middle East poses a real threat to the existence of Israel except Israel itself).  ISIS poses a threat to the non-glassy nature of Syria and Iraq, but that's only if they are able to form any sort of stable state, which I've already mentioned isn't going to happen.

There's also an economic concern. If they managed got acquire control of oil prices (they can already influence them), they could exert political pressure similar to what Russia used to do with natural gas. Though it is a less important concern, we likely don't want that, either.

If you think ISIS, with limited influence in the middle of no-man's land in Syria and Iraq, is capable of acquiring any sort of "control" over oil prices in a global sense, you really need a lesson in economics.  ISIS could shut off the taps in ALL of Syria and Iraq tomorrow and all it would really do is decrease the debt a few countries are incurring right now with oil below $50/bbl.  Iraq has 1/5th of the world's proven oil supplies, with a tiny fraction of them actually developed.  Canada has over 1/3, and we currently have major projects being deferred and held over because oil prices are so low. Really, all ISIS could do is flood the market further which isn't really a bad thing for anyone but countries relying on high oil prices to keep low taxes. Meh.

[Dragon]

You talk a lot about any carpet bombing and aerial destruction, to which I already have a response: NATO doesn't have the balls for that. There will be no carpet-bombing, no glassing, no nothing! NATO will outright refuse to hit any area remotely near civilians with anything but the most precise guided weapons. That's what they're doing right now, and that's all they're going to keep doing. Indiscriminate bombing with B-52s is beyond what NATO is willing to do. So are nuclear weapons, even of tactical sort. Russia, maybe, but they're not interested in the place right now. I would love to see ISIS being bombed into oblivion, but NATO will simply refuse to do that out of fear of harming civilians. I don't think ISIS would be dumb enough to enact any permanent infrastructure far enough from civilians for NATO to be able to hit it from the air. Remember the flak Israel got for hitting Hamas ammo dump inside a school? No NATO country would be able to do such a thing. So no. There will be no large-scale response. There should have been one long ago. Nobody had the guts then, nobody will have the guts a couple of years from now. The best shield against NATO bombs in the modern world are innocent children and civilians in general, no nuclear deterrent needed.

If left alone for long enough, ISIS will be able to threaten Israel. All its previous wars were not against fanatics like this. In none of those wars, Israel's enemies really "fought to death". ISIS very well might. Note, I'm talking much more long term than you are. I'm not worried about the next year, I'm worried about a few years after that. Possibly longer. ISIS will grow in strength unless something is done, and could eventually be able to take on Israel. Especially if it grows strong enough for other countries to start overlooking their ideology in favor of having a powerful ally.

ISIS is in no way comparable to NK. If nations fall to psychological stupidity, that's their problem. ISIS can't form a stable country without losing what makes it ISIS.  They only operate now through mobility - the moment they've created any sort of infrastructure is the moment they get introduced to aerial ordinance.  Air power alone, as is being exercised right this second, is more than sufficient to keep ISIS from posing any tangible threat to other countries. And no, I don't count the odd lone self-radicalized operative already in those nations.

They can change tactics without changing the core of their ideology, which is the real source of danger. It's quite popular in the Middle East, very radical and expansionist. They will continue to grow, and eventually will stop resembling what they are now. It might be unable to form a stable country in its current state, but it might change without becoming less dangerous. If they lose anything, it won't be threat that they pose to others.

[Luis Dias]

Examples of Japan and Germany are also not the finest, since those two countries were, before WW2, incredibly advanced culturally and educationally, they regarded themselves as elite people. And they were! Germany was, before WW1, the center of the civilized world. And even still, it wasn't easy. It took a lot of bold steps (Ich ein Berliner!) and a bloody cold war that sparked a lot of infusion of cash into Germany and Japan (Marshall...). Nation building from scratch, which is what we are talking about here, would be far more difficult, especially in this weird post punk cybernetic age crossed with post-apocalyptic landscapes that Iraq are. (For real, so many post apocalyptic sci fi stories could just be reframed like "Somewhere between Iraq and Afhganistan a man named Max just wants fuel for his car..." and it would work perfectly!)

[Dragon]

Of course, occupation is not guaranteed to work. History tends to roughly repeat itself, but no situation happened twice. Every situation is different somehow, we can speculate and deduce from past experiences, but we can't have certainty. Germany and Japan are not perfect examples, but they are valid arguments. I can't really find a case where a more primitive country was occupied for a long time and whether it brought results or not. Both Germans and Japanese think differently than people in the Middle East. Still, Japan had Western mentality successfully imposed on them (for Germany, the jump wasn't nearly as big). On the other hand, their honor system means that, as the defeated side, they had to agree to that. Arabs may be less susceptible. This is compounded by the fact Japan had no religious issues, Shinto is permissive of other faiths and religion in general plays a different role in Japanese society (Islam, on the other hand, is very "intrusive", with a multitude of strict rules, mandatory daily prayers and very little leeway for its believers). On yet another approach, Japan was technologically on par with America, Middle East is not. If the West was willing to invest in the region, it could greatly improve the quality of life there, possibly inclining people to warm up to the occupation.

I think that occupation is our best chance, strategically speaking, and a better choice than destroying the region. However, there's also an economic consideration. Occupations cost money. I have doubts on whether capturing the oil fields would recoup the cost. Likely not. The economic situation in Europe is sticky, and the US isn't doing as well as it'd like to, either. We're looking at over 20 years of supporting an occupying force, along with improving quality of life in the region and generally trying to keep it working. Being unable to pay for something doesn't usually stop politicians from doing it, but it seems that since the latest recession, everyone started to watch their money. This is part of the reason why I supported just exterminating the IS (especially earlier, when the economy was even worse). It's the cheaper option, to put it bluntly.

The way I see it, we have two semi-decent options. Occupation and destruction. NATO doesn't have money for the former and public support for the latter. It also doesn't have balls for either. So we're implementing a half-arsed solution and hoping that the region will sort itself out. I can't see anything good coming out of that. I just hope the Jewish Quarter in my city stays off their radar (it's mostly a historic site, there are a few Jews around, but hopefully not enough to warrant blowing it up).