The American public knows just about all it needs to know about the health of President Bush. The White House last week released results of the M.R.I. on his knee, which showed signs of arthritis and a malady called runner's knee. Earlier, there were results of his colonoscopy and of various physical examinations. There was also an account last year of the president's misadventure with a pretzel that lodged briefly in his throat, causing him to pass out. All of this information is a necessary part of keeping tabs on the president's health. By contrast, there is much we do...