BY CLIFFORD MAY As America's ambassador to the United Nations, John Bolton was the White House's most effective defender. Now, as an ex-diplomat, he has become among the administration's toughest critics. But he critiques from the right, not the left, which probably explains why the elite media are not eager to focus on what he has to say. The son of a Baltimore firefighter who attended Yale Law School on scholarship, Bolton combines a combative nature with a keen intellect. He is a conservative without the prefix - neither neo-con (he's skeptical about nation-building and democracy promotion) nor paleo-con...