Interpreting the Fourth Amendment is a task to turn judges into metaphysicians. How, for example, does the guarantee against "unreasonable searches and seizures" apply to a citizen's garbage?
In Highgrove, Calif., last winter, a neighbor tipped the police that Mr. and Mrs. Robert Edwards had on their back porch a suspicious package containing "a dark green vegetable substance that appeared similar to alfalfa but did not smell like alfalfa." Without a search warrant, the police rummaged in the Edwardses' backyard trash cans and found a few pinches of pot. They forced their...