The average scientific dispute is a joust in obscurity, a clash over technical matters that few but the immediate combatants grasp or are even aware of. Dr. John H. Marburger III, President Bush's science adviser, might relish a dose of that obscurity right now. Instead, he has become the first line of defense against accusations that the Bush administration has systematically distorted scientific fact and stacked technical advisory committees to advance favored policies on the environment, on biomedical research and on other areas like the search for unconventional weapons in Iraq. Dr. Marburger says that pattern is illusory, a product...