This short essay, delivered as the 2007-2008 Blackmun Lecture at Ohio State University, considers the Supreme Court’s suggestion in Michigan v. Hudson (2006) that developments in law enforcement since the 1960s have drastically undercut the need for the exclusionary rule. How does that notion square with what we know about the rule world of policing and criminal adjudication? Law enforcement has in fact changed substantially in recent decades, and largely for the better. Those changes may in fact justify significant shifts in how we think about and regulate the police. But simple considerations of scale, tied with anecdotal experience with the selective removal of the exclusionary sanction, cast doubt on the Court’s suggestion.