I would have to agree with CavGuy about "a little COIN may be worse than no COIN at all." This is a worthwhile consideration when we discuss the larger picture in Afghanistan--of ceding whole areas and conducting something called CT in those areas.

However, taking this line of thinking beyond just Afghanistan, and beyond just COIN, I'd make the assertion that we (the US) have never done "economy of force" missions very well, unless they were stand-off (air and fires based) and that the current "information environment" makes it even harder.

The bottom line of economy of force operations is that we apply the minimum resources necessary and our usual goal in that specific area is, at best, to maintain the status quo, so we can apply decisive force elsewhere. In real terms, this means sending people to die for no immediate or apparent gain—or at least we have to describe it as such. Witness the whole Italian campaign in WWII. Arguably, that sucked up more resources than it did hold Germans in place—primarily because we had to maintain the offensive and show progress in order to validate the losses we were suffering.

Once we place significant troops in an area (and we can argue what number equates to significant), there is an expectation on the part of our society, if not political leaders, that they will be supported and not placed under undo risk. The requirement to have fires, logistics and reinforcements readily available ends up pulling in such strength and effort that it undercuts any notion of “economy of force.”