This article discusses the tensions between the federal government and the states in several areas in modern commerce where consumers and business have competing interests. First the article discusses traditional approaches to express preemption and the constitutional and economic policy behind its uses by Congress. Even when Congress expressly preempts state law, courts narrowly construe those provisions, thus establishing a presumption against preemption. In this realm, state lawmakers and regulators still flex their authority. The article then looks at three recent federal and state conflicts in e-commerce to discuss the current uses of preemption by Congress and whether they are consistent with the traditional approach. This analysis provides instructors a new, different, and exciting way to approach this government regulation topic that can otherwise seem theoretical and remote to students. For legal studies faculty who are committed to the legal case method tradition, the article discusses numerous new preemption cases that illustrate the federal/state conflicts typically analyzed in legal environment or business law courses. For faculty who teach in integrated business programs, or who use business cases to teach business law, the article also suggests how this topic can be used to integrate legal studies issues into core business content. (Contains 1 table and 106 footnotes.)