Mugged by reality and realism

Over at Bloggingheads.tv the thuggish Jim Pinkerton throws some reality in the gracious Ann Althouse' face. Ann is a big-hearted person, and I can't help but feel for her idealistic Wilsonian vision in the face of Pinkerton's cold realist calculus. But Pinkerton is right on many points, and importantly, he seems to place less emphasis on what should be done, as opposed to the facts we have to work with in making our decisions. Similarly, today Matthew Yglesias rubs it in the face of a commenter who declares that the Sky is Falling! On that foundation does not a sound foreign policy rest.