Courts naturally and necessarily turn to analogical reasoning to incorporate cyber-technologies into existing doctrinal rules. And when it comes to criminal procedure, the preferred form of legal reasoning has been mono-analogous. The term “mono-analogical” designates a brand of analogical reasoning where only a single dimension of a subject is mapped. I argue that the prevailing mono-analogical approach to cyber-issues (which places near-exclusive emphasis on a technological instrument's functional role) is indeterminate, undisciplined, and in disregard of the subtler lessons of landmark Fourth Amendment opinions such as United States v. Knotts and Kyllo v. United States.

This article suggests, as an alternative, a poly-analogous approach: one that respects the necessity for functional comparisons but at the same time gives due credit to the practical dimensions of emerging technologies. Such practical dimensions can be incorporated into prevailing doctrine with little difficulty. The “analogy breaker,” applicable across the spectrum of criminal procedure doctrine, will help courts identify the essence of precedent and, as a result, effectively mediate old criminal procedure rules and new technologies.