As I said, I don't think you can go into isolationism after you've opted to go in and mess with things. Unfortunately, we've been messing with things for so long, and it's not working, that we can't exactly just pull back everything overnight and yell "Best of luck with everything!" as we softly close the door. It is possible to, though it would never be acceptable with the public, to provide a show a force and still remain isolationist. We would just have to over-respond every time someone poked at us. Radical Islam would eventually realize that we are not to be messed with when the slightest provocation ended up with a massive retaliation. But this is all moot - we're way past this point now, and there is no good solution.
So jihadists are America's fault? A "show of force" and "massive retaliation" are two totally different things militarily. The latter would eventually work, but only if applied to attacks on our vital national interests, not just direct assaults on our homeland. It's not moot because we need to learn from our mistakes.
No, since jihadists, for lack of a better term, have been around since the days of Muhammad in 600 A.D. But I do believe that the policy/actions of the United States has exacerbated the issue materially. Homeland, citizens, interest. But responses to interests would have to be significantly different - maybe even covert. It's moot because we'll never learn from our mistakes. Politicians are not capable of it.
So should we walk on eggshells and ask jihadists for permission to act in our interests going forward? There's a time and a place for covert operations but why should we shy away from openly defending our interests? They will when things get bad enough.
No, we should let them kill each other and not get involved. Wasn't it Johnson who once said (and then went back on) the words "I will not send American boys 10 or 12 thousand miles away to do what Asian boys ought to be doing for themselves"? Because not everything calls for open warfare and bloodshed, not to mention the billions of dollars in spending (which we can no longer afford). What's that saying about hoping in one hand and shitting in the other to see which one fills up first? IF they learn, and it's a big IF, it will be too late.
Saying that "we should let them kill each other" is naive and ignores the nature of the threat. Nor does it address how we protect our interests in the region. Hope is not a method. You dodged my question, which was why should we shy away from openly defending our interests? (Which you implied when you wrote "But responses to interests would have to be significantly different - maybe even covert.") Your second point about cost is absolute nonsense. We need to spend whatever it takes.
The debate between Tsing and 666 is indicative of how we're trying to manage our current problem in the ME. There just aren't any good choices. On one hand we argue that we should just butt out and let them kill each other off. Problem with that is that they won't kill each other fast enough or in great enough numbers to bring it to an end. There will be a winner, and that winner will be the bad guys. The other side of the argument is just blast them all off the face of the earth and be done with it. Problem with that is it just kills far too many innocent people. They ain't all bad, and I think most are just scared shitless. Who wouldn't be? We gotta' face facts. We really screwed the pooch this time. Should have never went in, should have never stayed, having stayed shouldn't have left entirely, shouldn't have tried to reason with the bad guys. Every wrong move to make, we made. Do nothing and the bad guys get bigger and stronger. Dipping our toe in does nothing. I'm tellin' ya, we're gonna' fight this fight one way or the other, cause guess what, the enemy has a choice too, and they choose to fight. They ain't gonna' stop. Sorry fella's but we need boots on the ground, and lot's of'em. Just how it plays out. Nothing else is going to work.
You can call it naive if you like. I call your method arrogant. I guess we'll agree to disagree. I didn't dodge anything. "Interests" is by definition, ambiguous. Some interests could require covert action - ie, supporting an ally politically and even financially. Other attacks on "interests" might require more of a direct effort because of importance. Of course "interests" would have to be decided on by someone. Who will that someone be? You? Politicians? When it comes to citizens or a direct attack on our territory, that is a much more black and white area. Am I still "dodging" or is that sufficient for you to understand my viewpoint? Fortunately, your opinion (because that is what it is) about it being nonsense isn't shared by everyone.
Let's assume that ISIS and allied groups manage to seize and keep most of sunni Iraq. The next assumption seems to be that they will immediately mount a terrorist attack on our homeland. But what if they just act pretty much as Iran has? Sponsor some bad groups and fund terrorism here and there but mainly concentrate on running their part of Iraq and stealing as much money as possible. Isn't that a likely scenario? It's exactly what the sunni's who run Saudi Arabia and the Gulf states do. I have no idea which version plays out, but before committing tens of thousands of troops yet again to another pointless war, shouldn't we find out?