Jim Harper of the Cato Institute writes:
Everybody’s wrong. That’s sort of the message I was putting out when I wrote my 2008 American University Law Review law review article entitled “Reforming Fourth Amendment Privacy Doctrine.”
A lot of people have poured a lot of effort into the “reasonable expectation of privacy” formulation Justice Harlan wrote about in his concurrence to the 1967 decision in U.S. v. Katz. But the Fourth Amendment isn’t about people’s expectations or the reasonableness of their expectations. It’s about whether, as a factual matter, they have concealed information from others—and whether the government is being reasonable in trying to discover that information.