Full-text available at SSRN. See link in this record.This essay is part of a symposium on a series of Supreme Court decisions during the 1990s that reinvigorated, and at times reinvented, federalism-based limits on congressional power, a constitutional doctrine that has lain dormant since a trilogy of post-New Deal decisions repudiating the Court’s Lochner era jurisprudence of reserved state powers. The long term practical impact of the recent decisions remains unclear, even if the basic contours of the new doctrine are fairly discernable. Indeed, the new federalism raises more questions than it answers, and its final frontiers will depend on how the Supreme Court resolves this next generation of federalism questions. I focus on one subset...