And should! The world is too big to be "filled" by United States. Realistic policy is not to be everything for everyone - it is to participate in or manage multipolar balances. If done cleverly the power of others can be leverage to the advantage of the clever side. That is why Reagan administration was supporting Saddam Hussein.
If United States continue to follow old Spanish interventionist Great Armada strategy it will spend the resources and will cease to be a great power.
Well, if we don't fill the vacuum as much as possible, maybe the Chinese PLA will do it... or the Caliphate, or the EU army... who knows???
But if we're gonna be bitching that some of the architects of the current US foreign policy are pro-choice or favor homosexual marriage, we should be getting ready our red flags with the 5 stars to welcome the "liberating" army.
Shut up!!!
Forgotten by some is the fact that the Communist leadership (perhaps gone in Russia, but VERY much alive and well in PRChina) had a plan.
The plan was quite simple: spread US forces thin by fomenting problems all over the globe, then watch the USA exhaust its military and financial resources.
On cue, the apple drops.
You don't have to be a Commie to appreciate the plan's elegance, simplicity, and viability. Actually, it's a hell of a lot cheaper than building a bunch of missiles and navies.
Economy-minded types, those Commies.
We're not a hyperpower because we want to be. We're a hyperpower because no other nation on the planet has the ability and/or the willingness to play a stabilizing role.
We're stuck with interventionism until other nations step up and do their part.