WASHINGTON - Vice President Cheney's chief of staff, Lewis "Scooter" Libby, has been pegged as a possible leaker of the name of CIA (news - web sites) operative Valerie Plame to a syndicated columnist, according to a new book by former ambassador Joseph C. Wilson IV, Plame's husband. In "The Politics of Truth," to be published Friday, Wilson says Libby is "quite possibly the person who exposed my wife's identity," according to The Washington Post, which obtained an early copy. Wilson writes that a "workup" of his background was done by the White House in March 2003, after his public...