The right of the people to be secure
in their persons, houses, papers and
effects, against unreasonable searches
and seizures, shall not be violated . . .
The constitutional command erects a wall of privacy that U.S. police cannot breach without a valid search warrant. But even so, the wall has gaping holes. Police are free to use evidence gained by peering in the locked windows of a private house; they can also plant electronic "bugs" on outside walls to record conversations inside. Unless they unlock the windows or pierce the...