An application was submitted to a magistrate judge for the Eastern District of California requesting an "anticipatory" search warrant, so-called because it is based upon the probable cause that at some time in the future (but not at present) certain evidence of a crime will be located at a specified place).

A grand jury for the Eastern District of California indicted Grubbs on one count of "receiving a visual depiction of a minor engaged in sexually explicit conduct.

[5] Because the postal inspectors failed to present the application affidavit—the only document in which the triggering conditions were listed—to Grubbs or his wife, the court ruled that the "warrant was...inoperative, and the search was illegal."

[6] The judgment was unanimous as to the eight members of the Court participating,[7] as were the first two parts of Scalia's opinion that upheld the constitutionality of anticipatory warrants in general.

Regarding the warrant's failure to describe that triggering condition, Scalia wrote in Part III of the Court's opinion that, contrary to the Ninth Circuit's ruling, the Fourth Amendment does not have a general "particularity requirement."

Warrants must only describe with particularity "the place to be searched" and "the persons or things to be seized," and the Court stated that it had previously rejected attempts to expand that scope.

Finally, the defendant claimed that the omission of the triggering condition prevents the person whose property is being seized of being notified of the lawfulness of the search and seizure.