Dr. Sowell describes the critical differences between interests and visions. Interests, he says, are articulated by people who know what their interests are and what they want to do about them. Visions, however, are the implicit assumptions by which people operate. In politics, visions are either constrained or unconstrained. A closer look at the statements of both McCain and Obama reveals which vision motivates their policy positions, particularly as they pertain to the war, the law, and economics.
This is also a great exploration of the difference between constrained realists and unconstrained visionaries, traditionalists vs. central planners, the empirical world vs. the normative.