At the nation’s founding, search warrants and the concept of suspicion were well entrenched as a means of limiting governmental search power. This tradition largely explains why today’s Fourth Amendment law includes two foundational black letter rules: the presumptive warrant requirement and the presumptive suspicion requirement. Unfortunately, neither of these rules is correct. Certainly they have historical support, especially in the common law. But whether they reflect the totality of our historic experience is questionable, especially when civil search practices are considered. More importantly, modern developments—such as urban life and technological advancements, the rise of the regulatory state, and post-9/11 security concerns—have sufficiently changed circumstances so that these rules are now unworkable. Indeed, in today’s world these rules are now demonstrably wrong. Worst of all, adhering to them has prevented us from formulating a more coherent Fourth Amendment jurisprudence. This Article is a call to arms. It challenges us to recognize that a new paradigm now confronts us, in which reasonableness serves as the constitutional touchstone for all governmental searches, and where neither warrants nor suspicion can be expected to serve as primary mechanisms for protecting Fourth Amendment values. Therefore, we must confront the need to identify new ways of assuring adequate Fourth Amendment protections. To that end, the Article concludes by offering some broad guidelines to start us on the way.