Perhaps the most important element of James Buchanan’s contribution to constitutional economics is his differentiation between pre- and post-constitutional levels of decision-making. At first glance, a tension may appear between those two levels of analysis. In one, the rules by which we live are up for debate, allowing us to exercise our creative and imaginative capabilities in constitutional construction. In the other, the rules are viewed as fixed, and we are left simply to treat them as constraints. This paper explores three key elements of Buchanan’s thought that allow him to navigate successfully between the two levels. The first is the importance of “the relatively absolute absolute”, a concept learned from his mentor, Frank Knight. The second is Buchanan’s approach to “truth judgments” in politics, and their status in our political discussions. Third, we draw on Buchanan’s insights in his 1959 paper “Positive Economics, Welfare Economics, and Political Economy” to show how political economists should participate in this decision-making process—not as expert philosopher-kings, but as co-equals with their fellow citizens. Finally, we illustrate Buchanan’s system of thought in action by presenting two case studies: Virginia education policy in the wake of Brown v. Board of Education, and the 1928 Supreme Court ruling in Miller v. Schoene.

詹姆斯·布坎南（James Buchanan）对宪法经济学的贡献中，最重要的因素也许就是他在宪法制定前后的决策水平之间的区别。乍一看，这两个分析级别之间可能会出现紧张关系。第一，我们赖以生存的规则尚待辩论，这使我们能够在宪政建设中发挥创造力和想象力。在另一方面，规则被视为固定的，我们仅将它们视为约束即可。本文探讨了布坎南思想的三个关键要素，这些要素使他能够在两个层次之间成功地导航。首先是“相对绝对绝对”的重要性，这是从他的导师弗兰克·奈特那里学到的。第二个是布坎南的政治“真相判断”方法，及其在我们政治讨论中的地位。第三，我们借鉴布坎南（Buchanan）在其1959年的论文《正经济学，福利经济学和政治经济学》中的见解，以表明政治经济学家应如何参与这一决策过程-不是作为专家哲学家，而是与他们一样本国人。最后，我们通过展示两个案例研究来说明布坎南的思想体系：紧随其后的弗吉尼亚州教育政策布朗诉教育委员会一案，以及1928年最高法院在Miller诉Schoene案中的裁决。