In a novel case, the Ninth Circuit ruled on July 6, as amended July 25, that government surveillance of Internet Protocol (“IP”) addresses visited, to/from addresses of emails, and the total volume of information sent to or from an email account does not violate the Fourth Amendment. United States v. Forrester, No. 05-50410, — F.3d — (9th Cir. July 6, 2007). The ruling does not affect the requirement that the government obtain a search warrant before searching the actual content of that Internet traffic.

The defendant in United States v. Forrester, Dennis Louis Alba, was charged and convicted of various federal offenses relating to the operation of an Ecstasy-manufacturing laboratory. During the government’s investigation of Alba, it installed a device on Alba’s computer that gathered the IP addresses of the websites he visited, the to/from addresses of his emails, and the total volume of information sent to or from his email account. In his appeal, Alba contended that the surveillance constituted a warrantless search in violation of the Fourth Amendment and fell outside of the then-applicable pen register statute. The Ninth Circuit addressed the merits of Alba’s first contention, but found it unnecessary to address the second.

The Ninth Circuit applied the Supreme Court’s analysis in Smith v. Maryland, 442 U.S. 735 (1979), in which the Court held that a pen register does not constitute a Fourth Amendment search. The Court so held because pen registers merely track phone numbers dialed and do not reveal the actual contents of conversations. Cf. Katz v. United States, 289 U.S. 347 (1967) (holding that one can have legitimate expectation of privacy in the contents of one’s phone conversations).  The Ninth Circuit reasoned that the government’s surveillance of Alba’s activity was “constitutionally indistinguishable” from surveillance via a pen register because accessing IP addresses involves the transmission and receipt of a unique identifier, which does not reveal actual content, via the third-party equipment of an internet service provider.  An Internet user therefore does not have a legitimate expectation of privacy in the IP addresses he or she accesses.

For the same reasons, the court found that surveillance without a judicial warrant of the senders and recipients of Alba’s e-mail and the volume of information flowing through his e-mail account did not violate the Fourth Amendment. The court also analogized to physical mail: the government may, without a warrant, note the addresses on the outsides of envelopes and the volume of mail sent to and from a particular address.

Interestingly, the Ninth Circuit opined that unwarranted surveillance of another form of webpage identification, the uniform resource locator (URL), could pose Fourth Amendment problems. URLs identify particular documents within a website and often contain the search terms a user might employ to find that particular document. Surveillance of URLs therefore is more likely to reveal the content of communications than surveillance of IP addresses and is more likely to violate Katz.