Ross Douthat, in a post a couple of days ago, seemed to lay the blame for the administration's Iraq missteps on evangelical Christianity:

[T]he failures of the Bush era haven't just been the result of cronyism, incompetence, and the corruption that festers at the intersection of big government and big business. They have also been evangelical failures, flowing from a surfeit what [Wilfred] McClay calls the "moral radicalism" of the evangelical mind, which is a bit too eager to unleash that "fire in the minds of men" that Bush cited in his Second Inaugural Address. . . .  [T]he Iraq War will stand for a long time as a monument to the potential excesses of evangelical thinking - and when it comes to our foreign policy, I hope the next GOP President partakes of a little less of Bush-style missionary zeal, and a little more of that old-time conservative religion.

To which one obvious objection is that Dick Cheney and Donald Rumsfeld, who appear to have driven the biggest blunders, are hardly evangelicals, or religious at all so far as I can tell. (I once sat in a Sunday school class with Rumsfeld in a Chicago Presbyterian church while he was CEO at Searle Corp., but I got the distinct impression his wife had dragged him along.)  Arrogance and overconfidence can come from many sources, some of them a lot darker than "evangelical missionary zeal."  Douthat later follows up, reiterating but with caveats:

I didn't mean to single out evangelicals as a brand-new scapegoat for the Iraq War -- replacing the Jews, the neocons, the oil industry, the Saudis, Bush's daddy issues, the liberal me-tooers, and so on and so forth. Our invasion of Iraq was, like many wars, overdetermined, with all sorts of people (myself included, until very late in the game) supporting it for all sorts of reasons. But George W. Bush was and remains the central actor in the drama, and I think his personal religious instincts - reform-minded and idealistic, in the mode of evangelicals like William Wilberforce - have at least as much explanatory power as the calculating realpolitik of Cheney or the liberal moralism of Wolfowitz.

Of course, evangelicalism also gets blamed for instilling in Bush a Left Behind-style, "let's bring on Armageddon and Jesus's second coming" attitude, which is the opposite of optimstic reformism.  So the evangelicals can't win for losing.

Douthat then quotes McClay:

There is not much of [Reinhold] Niebuhr, or original sin, or any other form of Calvinist severity, in the current outlook of the Bush administration.  That too is a reflection of the optimistic character of American evangelicalism, and therefore of evangelical conservatism. . . .

But conservatism will be like the salt that has lost its savor, if it abandons its most fundamental mission -- which is to remind us of what Thomas Sowell called "the constrained vision" of human existence, which sees life as a struggle, with invariably mixed outcomes, full of unintended consequences and tragic dilemmas involving hopelessly fallible people. . . .  As the example of Niebuhr suggests, such a vision need not reject the possibility of human progress altogether. . . .  But it does suggest that it is sometimes wise to adopt, so to speak, a darker shade of red, one that sees the hand of Providence in our reversals as well as our triumphs.

Bringing this back to MOJ ... One Catholic commenter on Douthat's site joined in pinning the Iraq problems on the evangelicals:

Most Catholic conservatives are imbued with an Augustinian distaste for utopian schemes, and seem willing to at least tolerate worldy imperfections, for lack of a better term. Evangelicals, meanwhile, as Ross wrote, do have a more missionary zeal to transform the world.

But I doubt that "Catholicism right, evangelicalism wrong" is much of an answer here either.  The most vocal Catholic conservatives in America have defended the Iraq war throughout.  It's true that George Weigel and Michael Novak defended going to war on pessimistic or "realistic" grounds (the perceived danger of WMDs) in addition to optimstic ones (the prospect of democratizing Iraq).  (See here and here.)  But it's hard not to see seeds of overconfidence in their method of analysis as well.  Both Weigel and Novak argued that there is no "presumption against war" in just-war thinking, and that if a war is justifiable -- under natural-law principles accessible to all persons of good will -- then it is not a "necessary evil" but rather a positive act of charity and, essentially, ought to be pursued with confidence.  This attitude doesn't necessarily lead to arrogance, but neither does it dispose one to be sensitive to the ironies and tragedies that accompany even efforts to do good -- as Niebuhr emphasized, channeling St. Augustine.  And that the good of removing Saddam can also generate many ironies and tragedies born of arrogance -- from inadequate troop commitments to Abu Ghraib -- is certainly a central lesson of the Iraq war.

My own view (here) is that things work best when a natural-law approach and an Augustinian realist outlook co-exist and interact, interpreting and correcting each other.  It seems to me that Iraq is a case where the application of natural law, in the form of just-war principles, needed to be filtered through, and applied in the light of, an Augustinian/Niebuhrian caution about the dangers of even well motivated acts.

Tom