Can the foreign policy establishment be defended?

Yesterday at NRO, the always-interesting Reihan Salam Josh Barro* offered a robust defense of inside-the Beltway thinking about economic policy — which he labels the "Washington Consensus" (NOTE:  not exactly the same thing as this Washington Consensus): 

While it contains a lot of errors, the Washington Consensus is right more often than it is wrong. Even more importantly, critiques of the Washington Consensus are wrong more of then than they are right—meaning that taking Washington Establishment down a peg will tend to do more harm than good….

Since the Washington Consensus contains lots of errors, there are outsiders with better ideas in these areas. Nominal GDP targeting, championed by Scott Sumner and others, would constitute a major improvement of monetary policy. Higher capital requirements and a tax on financial institutions that benefit from government backstops, among other reforms, would reduce systemic risk in the banking sector.

But the question is, would empowering outsiders at the expense of the establishment tend to replace the Washington Establishment’s biggest policy errors with outside wisdom? Or would it more often gut sound-but-unpopular policy and replace existing errors with bigger errors?

There are numerous policy areas where the hegemony of the Washington Establishment is the only thing saving America from popular but terrible ideas—trade, immigration, foreign aid.

I tend to agree with Reihan, particularly with his TARP example.  What I’m wondering is whether this holds true with foreign affairs as well.  Let’s face it, the foreign policy community (myself included) supported the 2003 invasion of Iraq.  Clearly, we have made Very Big Mistakes.  Foreign policy wonks outside the mainstream are very fond of claiming that being outside the mainstream is evidence that they’re right.  There are also many areas where the foreign policy consensus seems unsatisfying at best or catastrophic at worst. 

That said, it’a far from clear to me that populist foreign policy responses would necessarily be all that much better.  One could argue that, in toto, the American public is pretty damn realist — but I doubt that a populist foreign policy would actually resemble realpolitik.  The problem gets back to Salam’s point — even if there is mass discontent with the foreign policy establishment, there is not necessarily a lot of consensus about what should be in its stead.  Some critics would likely prefer a radical retrenchment of American military power — combined with a similar retrenchment in economic openness.  Others would prefer a greater embrace of multilateral structures — regardless of whether they actually worked or not. 

My hunch is that more bad would occur than good — but I want to hear from readers on this.  Is there such a thing as foreign policy "common sense"?  And, if so, would we see it implemented if the foreign policy community was winked out of existence?   

*Yes, Barro is always interesing as well