Tom Klingenstein frequently, and correctly, points out that the first step in winning a war is to acknowledge that you are in one. Similarly, one might say that the first step in resisting encroaching tyranny is to understand what it looks like. If the American experiment in self-government is unprecedented (as the founders, as well as Lincoln, believed) then its transformation into something unjust and oppressive would also be unprecedented. To notice the signs of America’s descent into illiberalism—assuming such a thing can be contemplated—it would not be sufficient merely to examine the historical record of how totalitarianism emerged in...