The Supreme Court begins the twenty-first century with increasing use of a cramped approach to Fourth Amendment interpretation. That approach, championed by Justice Scalia, gives determinative weight to outdated common law rules from the framing era in assessing the reasonableness of searches and seizures. In the annual James Madison Lecture, Judge Blane Michael urges a fundamentally different—yet still traditional— approach. He argues that Fourth Amendment interpretation should be guided by the basic lesson learned from the mischief that gave birth to the Amendment in 1791: Namely, there is a need for constitutional protection against intrusive searches of houses and private papers carried out under grants of open-ended discretion to searching officers. This need for Fourth Amendment protection remains compelling in today’s ever more interconnected world. Above all, the Court should not weaken the Fourth Amendment’s protection by exclusive use of antiquated common law rules from the framing era.