You can weigh legitimate pro's and con's for any situation, but the key word there is "legitimate". And arguments along the lines of "no nation building", "we shouldn't have been there in the first place", and "no interventionist policies" speak to that legitimacy. And that's the plain ol' simple facts of the matter.
Except for all three account nothing for the fact that we HAVE been nation building, we ARE there, and our entire foreign policy and economy is predicated off of active foreign action.
Simply because you dislike these things don't mean they're not occurring.
What you're suggesting is the equivalent of of having a die hard junky coming off everything he's on cold turkey because to hell with the detox, to hell with the high likelihood of death, by god its a legitimate and well principled notion to not be on drugs and therefore there is no harm in immediately pulling him off it.
Personally, I think such an idea is idiotic.
We have invested significant resources, both in gold and blood, in the reconstruction of Iraq. It is irresponsible to those that died, those that have been injured, and those of us that have helped finance this to basically flush it in the toilet without any kind of credence given to what has already been spent and how best to make the most of that situation. If we examine this and find that immediate pull out IS the most effective way, because the opposite choice will more than double what we've already invested thus making it best to cut our losses, no problem. But what I would not want, nor do I think is logical, to simply end it based on principles of what we THINK should've happened 7 years ago that are made without any comprehension or care for the present nor for what's occured in the past 7 years.
If I purchase a house that is way more than I should have paid for one, and I've been scratching by and going into debt in other ways for the past 7 years I would be idiotic to simply stop and go "You know what, I shouldn't have bought this house in the first place. Screw it, I'm just abandoning it". All that does is cement that I have no return at all, in any tangible way, with the 7 years I've scraped by trying to maintain that house. Now, if I look into it and have a reasonable belief that its going to take me another 7 years to get close to financial stable with this house which would likely end up not working and nearly ruining me, yes, absolutely, then I'd abandon it. However, if I look into it and find out that another year or two of scratching by and I will actually have it paid off, which won't remove the debt that I've gotten myself into but will at least now give me a place that I can live without having to make payments thus freeing up resources to pay off said debt...then I'd be a fool to abandon it simply on the principle that I shouldn't have paid for it in the first place.
Which is why I absolutely see what we're doing right now as the right thing to do in Iraq NOW, today, in THIS reality that we are actually existing in and living in for the past 7 years. Take this next year and a half to continually, slowly, draw down our forces...first our major combat forces, then slowly with the support forces. Continue to give aid and support to the Iraqi government to attempt to maintain a key diplomatic ally in an important international locale while hoping that our support will reduce the chance of the state failing and causing a hotbed to be created that could severely impact our national security. Look into possibly establishing a base there, while counter acting the cost by looking for bases to close in locations of the world where the strategic advantage of having a base and thus air space is not as great. Beyond said base, remove our forces by the start of 2012 and let the dice fall. By that point it is realistic that we have our BEST shot at both cutting ties AND having successful gains (even if its gains that keep us in the negative in your mind, its still more than what we'd possibly have from a direct immediate pull out) as we allow for a reasonable steady transition as we ramp down and Iraq ramps up.
Would I prefer we have not performed such nation building in the first place? Without question. Do I think going forward that should be our standard policy? Absolutely. Do I think those two things dictate that we should just immediately throw down all we've done in Iraq and run high tailing out of there without a care for it in the world based on nothing but "principle". Not a bloody chance.