Walter E. Williams, a prominent conservative economist, author and political commentator who expressed profoundly skeptical views of government efforts to aid his fellow African-Americans and other minority groups, died on Tuesday on the campus of George Mason University in Virginia, where he had taught for 40 years. He was 84.His daughter, Devon Williams, said he died suddenly in his car after he had finished teaching a class. She said he had chronic obstructive pulmonary disease and hypertension.As a public intellectual, Mr. Williams moved easily between the classroom and public forums that gave him wide reach. He wrote a syndicated column,...