During the past twenty years, the Supreme Court has issued a series of seemingly irreconcilable, sometimes unfathomable, opinions concerning federal preemption of state-law product liability suits involving various types of federally regulated products. The products involved in these cases—which have gone both ways on preemption—have included cigarettes,1 medical devices,2 motor boats,3 automobiles,4 pesticides,5 prescription drugs,6 and now, in Bruesewitz v. Wyeth LLC, No. 09-152 (Feb. 22, 2011), vaccines. Some of these cases involve “express preemption,” where Congress has included in the text of a federal regulatory statute a preemption provision that bars, either explicitly or as a result of judicial interpretation, imposition of certain types of state tort liability upon product manufacturers. Other cases involve “implied preemption,” where a statute does not contain a preemption provision, but congressional intent to preempt state tort liability is judicially inferred due to an implicit conflict with the objectives or operation of a federal regulatory scheme.