formation voluntarily conveyed to the banks and exposed to their employees in the ordinary course of business ( emphasis added).

Justice Lewis Powell United States v. Miller, The Miller ruling was applied to electronic communication a few years later in the case of Smith v. Maryland (1979). In this case, Michael Lee Smith burglarized a woman’s home and then made harassing telephone calls to her after the fact. In response to a request from investigators, the telephone company installed a pen register at the central office that served Smith’s home telephone line. A pen register is a device that records all of the numbers dialed from a given telephone line. In this particular case, the pen register captured the victim’s phone number being dialed on Smith’s telephone line; as a result, a warrant for a search of Smith’s home was obtained, evidence was found, and Smith was subsequently convicted of robbery. Smith appealed, claiming that the use of the pen register violated his Fourth Amendment rights. The Supreme Court disagreed. On the basis of the Katz reasonable expectation test and the results of the Miller case, Justice Blackmun wrote that:

 

First, it is doubtful that telephone users in general have any expectation of privacy regarding the numbers they dial, since they typically know that they must convey phone numbers to the telephone company and that the company has facilities for recording this information and does in fact record it for various legitimate business purposes (emphasis added).

Justice Harry Blackmun Smith v. Maryland, 442 U.S. 735 (1979)

Trace Devices.b
Title I covers the content of elec-
tronic communication, and generally
requires a warrant for the disclosure of
the content. Title II, sometimes referred
to as the Stored Communications Act
(SCA), covers stored wire and electronic
communications, as well as transac-
tional records. Title III, sometimes re-
ferred to as the Pen Register Act, covers
pen registers and related devices.

There has been a great deal of court
time spent debating which of the three
titles applies to the information col-
lected by a cellular network. This is
an important issue, as it determines
the legal burdens that law enforce-
ment must overcome to obtain the
data. Title II has been found to cover
historical cell site data.c Historical cell
site data is a list of the cell sites visited
by a subscriber up until the point in
time that the request by law enforce-
ment is made. According to Title II,
law enforcement agencies can obtain
this information by providing “specific
and articulable facts” showing that the
information is “relevant and material
to an ongoing investigation,” a proce-
dural hurdle that is substantially lower
than the “probable cause” require-
ment for a warrant.d

IllustratIon By aleX WIllIaMson

By 1979, the Court had clearly distinguished privacy rights regarding the content of telephone calls from the rights accorded to their context. This distinction was embedded in the Electronic Communication Privacy Act of 1986 (ECPA12), which includes three titles that provide varying levels of protection for various types of electronic communication:

˲ ˲ Title I: Electronic Communications in Transit;

˲ ˲ Title II: Stored Electronic Communication; and

˲ ˲ Title III: Pen Register/Trap and
b A trap and trace device is similar to a pen reg-
ister, but instead of capturing numbers dialed
from a given number, it captures the numbers
of parties that dial to a given number.

d The details of the requirements for a warrant can be found in Rule 41 of the Federal Rules of Criminal Procedure.

e See In re Application for Pen Register and Trap/Trace Device with Cell Site Location Authority, H-05-557M S.D. Tex., Oct. 14, 2005: [a] Rule 41 probable cause warrant was (and is) the standard procedure for authorizing the installation and use of mobile tracking devices. See United States v. Karo, (1984).

f See, for example, In re Application for an Order Authorizing the Extension and Use of a Pen Register Device, 2007 WL 397129 (E.D. Cal. Feb. 1, 2007); In re Application of the United States, 411 F. Supp. 2d 678 (W.D. La. 2006); In re Application of the United States for an Order for Prospective Cell Site Location Info., 460 F. Supp. 2d 448 (S.D.N. Y. 2006) (S.D.N. Y. II); In re Application of the United States of America, 433 F. Supp.2d 804 (S.D. Tex. 2006)

g See, for example, re Application of United States of America for an Order Authorizing the Disclosure of Prospective Cell Site Info., 2006 WL 2871743 (E.D. Wis. Oct. 6, 2006); In re Application of the United States of America, 441 F. Supp. 2d 816 (S.D. Tex. 2006); In re Application for an Order Authorizing the Installation and Use of a Pen Register and Directing the Disclosure of Telecomm. Records, 439 F. Supp. 2d 456 (D. Md. 2006).