Despite longstanding orthodoxy, the Constitution's enumeration of congressional powers does virtually nothing to limit federal lawmaking. That's not because of some bizarrely persistent judicial failure to read the Constitution correctly. It's because the enumeration of congressional powers is not a well-designed technology for limiting federal legislation Rather than trying to make the enumeration do work that it will not do, decisionmakers should find better ways of thinking about what lawmaking should be done locally rather than nationally. This Article suggests such a rubric, one that asks not whether Congress has permission to do a certain thing but whether a certain kind of lawmaking is more prone to pathology at the national or the state level. That inquiry could identify "suspect spheres": areas of policymaking where federal law calls for more justification than elsewhere. Federal legislation within suspect spheres would not necessarily be subject to judicial invalidation, but the judgment that legislation falls within a suspect sphere could underwrite softer forms of judicial resistance to nationalization. We illustrate the suspect-spheres model with a principle of federalism we call the corporate nondelegation doctrine, by which federal delegations of power to private corporations are to be treated skeptically. Early on, that principle animated Madison's opposition to the Bank of the United States and much of the Jacksonian approach to federalism. It later underwrote the Supreme Court's decision in Schechter Poultry. In the current century, the idea that the corporate nondelegation doctrine defines a suspect sphere helps explain otherwise puzzling judicial behaviors in federalism cases, including the presumption against preemption and the resistance to the individual mandate of the Affordable Care Act. By illustrating the possibility of a suspect-sphere approach, we suggest a tool that might be useful at a time of destructively polarized national politics, when rubrics for allocating some polarizing issue spaces to state-level decisionmakers might help lower the national temperature.