Page 42 - Privacy in a Cyber Age Policy and Practice

MORE COHERENT, LESS SUBJECTIVE, AND OPERATIONAL 27

in terms of e-mails, phone records, text messages, or, better yet, in terms
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of megabytes of information. The length of time of a wiretap is in effect
a crude but useable measurement of quantity. It is crude because there is
no strong correlation between the amount of time a tap is in place and the
amount of information collected; parties under surveillance may vary a
great deal in the extent to which they use a tapped phone. At the same time,
the metric is useable because it may not be practical to allow the authori-
ties to collect a specific number of calls or bytes of information. There are
many precedents for this approach. For example, at present the courts limit
wiretap orders to thirty days and grant additional thirty-day extensions in
accordance with the Wiretap Act. 41
In the case of e-mails and similar data, the Electronic Communications
Privacy Act of 1986 dictates that upon receiving a preservation request
from law enforcement officials, telecommunications providers shall “take a
‘snapshot’ of available electronic records in the account which is held pend-
ing legal process (such as a search warrant, court order, or subpoena). [This
information is] held for 90 days until legal process is obtained and submit-
ted to the provider. The 90 day preservation can be extended once more for
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an additional 90 days.” In short, there is ample precedent for using time
as a crude approximation for determining whether a collection of personal
information is acceptable or excessive.
Taking volume into account rather than merely asking whether a single
collection constitutes a search finds precedent in United States v. Jones. This
case concerned the installation of a GPS tracking device on Jones’s car after
a warrant obtained by the state had expired. The GPS tracking device was
activated constantly for twenty-eight days. The majority opinion did not
address the length of the GPS surveillance, but the concurring opinion by
Justice Alito stated that the length of the surveillance was a factor in his rul-
ing that this tracking constituted a Fourth Amendment search. Alito wrote,
“The use of longer-term GPS monitoring in investigations of most offenses
impinges on expectations of privacy. For such offenses, society’s expec-
tation has been that law enforcement agents and others would not—and
indeed, in the main, simply could not— secretly monitor and catalogue
every single movement of an individual’s care for a very long period. In
this case, for four weeks, law enforcement agents tracked every movement
that the respondent made in the vehicle he was driving. We need not iden-
tify with precision the point at which the tracking of this vehicle became a
search, for the line was surely crossed before the four-week mark.” 43
For the first approximation purposes attempted here, it is unnecessary
to provide specific numbers to limit various information collection opera-
tions. (For a brief discussion of the difficulties associated with arriving at
such specific numbers, see Chapter 1.) This is a task for another time. This