Date:    Fri, 24 Sep 1993 16:49:45 -0400 (EDT)
From:    denning@cs.georgetown.edu (Dorothy Denning)
Subject: Wiretap Article

The following article on wiretap laws and procedures was written in
response to the many questions and misunderstandings that have arisen
about wiretaps in the context of escrowed encryption as well as Digital
Telephony.  This article may be distributed.

Dorothy Denning
denning@cs.georgetown.edu
----------------------------------------------------------------------

                        WIRETAP LAWS AND PROCEDURES
             WHAT HAPPENS WHEN THE U.S. GOVERNMENT TAPS A LINE


                   Donald P. Delaney, Senior Investigator
                           New York State Police

                  Dorothy E. Denning, Professor and Chair
             Computer Science Department, Georgetown University

                      John Kaye, County Prosecutor
                      Monmouth County, New Jersey

        Alan R. McDonald, Special Assistant to the Assistant Director
        Technical Services Division, Federal Bureau of Investigation 


                           September 23, 1993
                                     


1.  Introduction

Although wiretaps are generally illegal in the United States, the
federal government and the governments of thirty seven states have been
authorized through federal and state legislation to intercept wire and
electronic communications under certain stringent rules which include
obtaining a court order.  These rules have been designed to ensure the
protection of individual privacy and Fourth Amendment rights, while
permitting the use of wiretaps for investigations of serious criminal
activity and for foreign intelligence.

This article describes the legal requirements for government
interceptions of wire and electronic communications and some of the
additional procedures and practices followed by federal and state
agencies.  The legal requirements are rooted in two pieces of federal
legislation: the Omnibus Crime Control and Safe Streets Act (Title III
of the Act (hereafter "Title III")), passed in 1968, and the Foreign
Intelligence Surveillance Act (FISA), passed in 1978.  Title III
established the basic law for federal and state law enforcement
interceptions performed for the purpose of criminal investigations,
while FISA established the law for federal-level interceptions
performed for intelligence and counterintelligence operations.  We will
first describe Title III interceptions and then describe FISA
interceptions.


2.  Title III Interceptions

Title III, as amended (particularly by the Electronic Communications
Privacy Act of 1986), is codified at Title 18 USC, Sections 2510-2521.
These statutes provide privacy protection for and govern the
interception of oral, wire, and electronic communications.  Title III
covers all telephone communications regardless of the medium, except
that it does not cover the radio portion of a cordless telephone
communication that is transmitted between the handset and base unit.
The law authorizes the interception of oral, wire, and electronic
communications by investigative and law enforcement officers conducting
criminal investigations pertaining to serious criminal offenses, i.e.,
felonies, following the issuance of a court order by a judge.  The
Title III law authorizes the interception of particular criminal
communications related to particular criminal offenses.  In short, it
authorizes the acquisition of evidence of crime.  It does not authorize
noncriminal intelligence gathering, nor does it authorize interceptions
related to social or political views.

Thirty seven states have statutes permitting interceptions by state and
local law enforcement officers for certain types of criminal
investigations.  All of the state statutes are based upon Title III
from which they are derivative.  These statutes must be at least as
restrictive as Title III, and in fact most are more restrictive in
their requirements.  In describing the legal requirements, we will
focus on those of Title III since they define the baseline for all
wiretaps performed by federal, state, and local law enforcement
agencies.

In recent years, state statutes have been modified to keep pace with
rapid technological advances in telecommunications.  For example, New
Jersey amended its electronic surveillance statute in 1993 to include
cellular telephones, cordless telephones, digital display beepers, fax
transmissions, computer-to-computer communications, and traces obtained
through "caller-ID".

Wiretaps are limited to the crimes specified in Title III and state
statutes.  In New Jersey, the list includes murder, kidnapping,
gambling, robbery, bribery, aggravated assault, wrongful credit
practices, terrorist threats, arson, burglary, felony thefts, escape,
forgery, narcotics trafficking, firearms trafficking, racketeering, and
organized crime.

Most wiretaps are large undertakings, requiring a substantial use of
resources.  In 1992, the average cost of installing intercept devices
and monitoring communications was $46,492.  Despite budget constraints
and personnel shortages, law enforcement conducts wiretaps as
necessary, but obviously, because of staffing and costs, judiciously.
  
2.1  Application for a Court Order

All government wiretaps require a court order based upon a detailed
showing of probable cause.  To obtain a court order, a three-step
process is involved.  First, the law enforcement officer responsible
for the investigation must draw up a detailed affidavit showing that
there is probable cause to believe that the target telephone is being
used to facilitate a specific, serious, indictable crime.

Second, an attorney for the federal, state, or local government must
work with the law enforcement officer to prepare an application for a
court order, based upon the officer's affidavit.  At the federal level,
the application must be approved by the Attorney General, Deputy
Attorney General, Associate Attorney General, any Assistant Attorney
General, any acting Assistant Attorney General, or any Deputy Assistant
Attorney General in the Criminal Division designated by the Attorney
General.  At the state and local level, the application must be made
and approved by the principal prosecuting attorney of the state (State
Attorney General) or political subdivision thereof (District Attorney
or County Prosecutor).  The attorney must be authorized by a statute of
that state to make such applications.

Third, the attorney must present the approved application ex parte
(without an adversary hearing) to a federal or state judge who is
authorized to issue a court order for electronic surveillance.  A state
or local police officer or federal law enforcement agent cannot make an
application for a court order directly to a judge.

Typically, a court order is requested after a lengthy investigation and
the use of a "Dialed Number Recorder" (DNR).  The DNR is used to track
the outgoing calls from the suspect's phone in order to demonstrate
that the suspect is communicating with known criminals.

Title III requires that an application for a court order specify:

   (a) the investigative or law enforcement officer making the
       application and the high-level government attorney authorizing
       the application;

   (b) the facts and circumstances of the case justifying the
       application, including details of the particular offense under
       investigation, the identity of the person committing it, the
       type of communications sought, and the nature and location of
       the communication facilities;

   (c) whether or not other investigative procedures have been tried
       and failed or why they would likely fail or be too dangerous;
   
   (d) the period of time for the interception (at most 30 days -
       extensions may be permitted upon reapplication);

   (e) the facts concerning all previous applications involving any of
       the same persons or facilities;

   (f) where the application is for the extension of an order, the
       results thus far obtained from the interception.

The process of making an application for a court order is further
restricted by internal procedures adopted by law enforcement agencies
to ensure that wiretaps conform to the laws and are used only when
justified.  The following describes the process for the FBI and the New
York State Police.

2.1.1  FBI Applications

In order for an FBI agent to conduct an interception, the agent must
follow procedures that go well beyond the legal requirements imposed by
Title III and which involve extensive internal review.  In preparing
the affidavit, the FBI agent in the field works with the field office
principal legal advisor and also with an attorney in the local U.S.
Attorney's Office, revising the documentation to take into account
their comments and suggestions.  After the documents are approved by
field office management, they are submitted to the Department of
Justice's Office of Enforcement Operations (OEO) in the Criminal
Division and to the FBI Headquarters (HQ).  At FBI HQ, the documents go
to the Legal Counsel Division (LCD) and the Criminal Investigative
Division (CID).  Within the CID, they are sent to the program manager
of the criminal program unit relating to the type of violation under
investigation, e.g., organized crime.  The program manager determines
whether the subjects of the proposed interception are worthy targets of
investigation and whether the interception is worth doing.  Attorneys
in the FBI's LCD and the DOJ's OEO further refine the documents.

After the documents are approved by the DOJ's OEO and by FBI HQ, they
are referred to the Deputy Assistant Attorney General (or above), who
reviews the documents and signs off on them.  At this point, the DOJ
authorizes the local U.S. Attorney's Office to file the final version
of the documents (application, affidavit, court order, and service
provider order) in court.  The U.S. Attorney's Office then submits the
documents and the DOJ authorization to a federal judge.  The entire
process can take as long as a month.

The following summarizes the people and organizations involved in the
preparation or approval of the application and the issuance of a court
order:

   1.  FBI agent
   2.  FBI field office attorney (principal legal advisor)
   3.  FBI field office management
   4.  Attorney in local U.S. Attorney's office
   5.  DOJ Office of Enforcement Operations (OEO)
   6.  FBI HQ Legal Counsel Division (LCD)
   7.  FBI HQ Criminal Investigative Division (CID)
   8.  DOJ Deputy Assistant Attorney General (or higher)
   9.  Federal District Court judge


2.1.2  New York State Police Applications

Within the New York State Police, electronic surveillance is conducted
by Senior Investigators in the Bureau of Criminal Investigation (BCI).  
In preparing an affidavit, the investigator works with the District
Attorney's Office (or, in the case of a federal investigation, the U.S.
Attorney's office) and with the BCI Captain of the investigator's
troop.  (Wiretap applications can be made and approved by the State
Attorney General, but this is unusual.)  The Captain assesses whether
review by Division Headquarters is necessary and confers with the
Assistant Deputy Superintendent (ADS) or Headquarters Captain for final
determination.  If Headquarters review is deemed necessary, then all
documentation is sent to the ADS along with a memorandum, endorsed by
the Troop Unit Supervisor and the Troop or Detail Commander, requesting
approval.  If Headquarters review is deemed unnecessary, then the memo
is sent without the documentation.  Once the ADS and District Attorney
(DA) approve the application, the DA submits the application to a judge
who grants or denies the court order.

2.2  Issuance of a Court Order

Not all judges have the authority to grant court orders for wiretaps.
In New Jersey, for example, only eight judges are designated as
"wiretap judges" for the entire state.  These judges are given special
training to be sensitive to personal rights of privacy and to recognize
the importance of telephone intercepts for law enforcement.

Before a judge can approve an application for electronic surveillance
and issue a court order, the judge must determine that:

   (a) there is probable cause for belief that an individual is
       committing, has committed, or is about to commit an offense
       covered by the law;

   (b) there is probable cause for belief that particular
       communications concerning that offense will be obtained through
       such interception;

   (c) normal investigative procedures have been tried and have failed
       or reasonably appear unlikely to succeed or to be too dangerous;

   (d) there is probable cause for belief that the facilities from
       which, or the place where the communications are to be
       intercepted are being used, or are about to be used, in
       connection with the commission of such offense, or are leased
       to, listed in the name of, or commonly used by such person.

In addition to showing probable cause, one of the main criterion for
determining whether a court order should be issued is whether normal
investigative techniques have been or are likely to be unsuccessful
(criterion (c) above).  Electronic surveillance is a tool of last
resort and cannot be used if other methods of investigation could
reasonably be used instead.  Such normal investigative methods usually
include visual surveillance, interviewing subjects, the use of
informers, telephone record analysis, and DNRs.  However, these
techniques often have limited impact on an investigation.  Continuous
surveillance by police can create suspicion and therefore be hazardous;
further, it cannot disclose the contents of telephone conversations.
Questioning identified suspects or executing search warrants at their
residence can substantially jeopardize an investigation before the full
scope of the operation is revealed, and information can be lost through
interpretation.  Informants are useful and sought out by police, but
the information they provide does not always reveal all of the players
or the extent of an operation, and great care must be taken to ensure
that the informants are protected.  Moreover, because informants are
often criminals themselves, they may not be believed in court.
Telephone record analysis and DNRs are helpful, but do not reveal the
contents of conversations or the identities of parties.  Other methods
of investigation that may be tried include undercover operations and
stings.  But while effective in some cases, undercover operations are
difficult and dangerous, and stings do not always work. 

If the judge approves the application, then a court order is issued
specifying the relevant information given in the application, namely,
the identity of the person (if known) whose communications are to be
intercepted, the nature and location of the communication facilities,
the type of communication to be intercepted and the offense to which it
relates, the agency authorized to perform the interception and the
person authorizing the application, and the period of time during which
such interception is authorized.  A court order may also require that
interim status reports be made to the issuing judge while the wiretap
is in progress.

2.3  Emergencies

In an emergency situation where there is immediate danger of death or
serious physical injury to any person, or conspiratorial activities
threatening national security or characteristic of organized crime,
Title III permits any investigative or law enforcement officer
specially designated by the Attorney General, the Deputy Attorney
General, or the Associate Attorney General, or by the principal
prosecuting attorney of any state or subdivision thereof, to intercept
communications provided an application for a court order is made within
48 hours.  In the event a court order is not issued, the contents of
any intercepted communication is treated as having been obtained in
violation of Title III.

In New York State, even an emergency situation requires a court order
from a judge.  However, the judge may grant a temporary court order
based on an oral application from the District Attorney.  The oral
communication must be recorded and transcribed, and must be followed by
a written application within 24 hours.  The duration of a temporary
warrant cannot exceed 24 hours and cannot be renewed except through a
written application.

2.4  Execution of a Court Order 

2.4.1  Installation of a Wiretap

To execute a court order for a wiretap, the investigative or law
enforcement officer takes the court order or emergency provision to the
communications service provider.  Normally, the service provider is the
local exchange carrier.  When served with a court order, the service
provider (or landlord, custodian, or other person named) is mandated
under Title III to assist in the execution of the interception by
providing all necessary information, facilities, and technical
assistance.  The service provider is compensated for reasonable
expenses incurred.  In light of rapid technological developments
including cellular telephones and integrated computer networks, the New
Jersey statute also requires the service provider to give technical
assistance and equipment to fulfill the court order.  This requirement
has not yet been tested in court.

Normally, the government leases a line from the service provider and
the intercepted communications are transmitted to a remote government
monitoring facility over that line.  In many cases, the bridging
connection is made within the service provider's central office
facility.  Alternatively, a law enforcement agency may request the
service provider to give the "pairs and appearances" (a place to
connect to the suspect's line) in the "local loop" for the suspect's
phone.  A law enforcement technician then makes the connection.

When a suspect's telephone is subject to change (e.g., because the
person is attempting to evade or thwart interception), then a "roving"
wiretap, which suspends the specification of the telephone, may be
used.  In this case, prior to intercepting communications, the officer
must use some other method of surveillance in order to determine the
exact location and/or telephone number of the facility being used.
Once determined, the location or telephone number is given to the
service provider for coordination and prompt assistance.  The officer
may not intercept communications randomly in order to track a person
(random or mass surveillance is not permitted under any
circumstances).

2.4.2  Minimization

Once any electronic surveillance begins, the law enforcement officer
must "minimize" -- that is, attempt to limit the interception of
communications to the specified offenses in the court order.  Prior to
the surveillance, a federal or state attorney holds a "minimization
meeting" with the investigators who will be participating in the case
to ensure that the rules are followed.

Minimization is normally accomplished by turning off the intercept and
then performing a spot check every few minutes to determine if the
conversation has turned to the subject of the court order.  This avoids
picking up family gossip.  Special problems may arise where criminals
communicate in codes that are designed to conceal criminal activity in
what sounds like mundane household discussion.  If an intercepted
communication is in a code or foreign language, and if someone is not
reasonably available to interpret the code or foreign language, then
the conversation can be recorded and minimization deferred until an
expert in that code or language is available to interpret the
communication.  Should a wiretap fail to meet the minimization
parameters, all of the evidence obtained from the wiretap could be
inadmissible.

2.4.3  Recording

All intercepted communications are to be recorded when possible.  As a
practical mater, law enforcement officers make working copies of the
original tapes.  In many instances at the state and local level, the
originals are delivered to the prosecutor's office and maintained in
the prosecutor's custody.  The copies are screened by the case officer
for pertinent conversations (e.g., "I'll deliver the dope at 8:00
pm.").  A compilation of the relevant conversations, together with the
corroboratory surveillances often provides the probable cause for
search warrants and/or arrest warrants.

2.4.4  Termination of Electronic Surveillance

Electronic surveillance must terminate upon attainment of the
objectives, or in any event within 30 days. To continue an interception
beyond 30 days, the officer, through a government attorney, must apply
for and be granted an extension based upon a new application and court
order.

When the period of a court order, or extension thereof, expires, the
original tapes must be made available to the issuing judge and sealed
under court supervision.  The tapes must be maintained in such fashion
for 10 years.

2.5  Notification and Use of Intercepted Communications as Evidence

Upon termination of an interception, the judge who issued the court
order must notify the persons named in the order that the interception
took place.  Normally, this must be done within 90 days, but it may be
postponed upon showing of good cause.  If the judge determines that it
would be in the interest of justice to make portions of the intercepted
communications available to the subjects, the judge may do so.

The contents of the communications may not be used as evidence in any
trial or hearing unless each party has received a copy of the
application and court order at least 10 days in advance of the trial,
and has been given the opportunity to move to suppress the evidence.  A
motion to suppress the evidence may be made on the grounds that it was
not obtained in complete conformance with the laws.

2.6  Reports

Within 30 days after the expiration or denial of a court order, Title
III requires that the judge provide information about the order to the
Administrative Office of the United States Courts (AO). Each year the
Attorney General (or a designated Assistant Attorney General) must
report, on behalf of the federal government, to the AO a summary of all
orders and interceptions for the year; reports for state and local
jurisdictions are made by the principal prosecuting attorney of the
jurisdiction.  The AO then integrates these summaries into an annual
report: "Report on Applications for Orders Authorizing or Approving the
Interception of Wire, Oral, or Electronic Communications (Wiretap
Report)" covering all federal and state electronic surveillance,
including wiretaps.  The 1992 report is about 200 pages and includes
information about each interception authorized in 1992, update
information for interceptions authorized in 1982-1991, and summary
statistics.  The summary statistics include the following data (numbers
in parenthesis are the 1992 figures):

   (1) number of interceptions authorized (919), denied (0), and
       installed (846)

   (2) average duration (in days) of original authorization (28) and
       extensions (30)

   (3) the place/facility where authorized (303 single family dwelling,
       135 apartment, 3 multi-dwelling, 119 business, 4 roving, 66
       combination, 289 other)

   (4) major offenses involved (634 narcotics, 90 racketeering, 66
       gambling, 35 homicide/ assault, 16 larceny/theft, 9 kidnapping,
       8 bribery, 7 loansharking/usury/extortion, 54 other)

   (5) average number of (a) persons intercepted (117), (b)
       interceptions (1,861), and (c) incriminating intercepts (347)
       per order where interception devices were installed

   (6) average cost of interception ($46,492)

   (7) type of surveillance used for the 846 interceptions installed
       (632 telephone, 38 microphone, 113 electronic, 63 combination)

   (8) number of persons arrested (2,685) and convicted (607) as the
       result of 1992 intercepts

   (9) activity taking place during 1992 as the result of intercepts
       terminated in years 1982-1991, including number of arrests
       (1211), trials (280), motions to suppress that are granted (14),
       denied (141), and pending (37), and convictions (1450) (there is
       a lag between interceptions, arrests, and convictions, with many
       arrests and most convictions associated with a wiretap that
       terminated in one year taking place in subsequent years)

Most of the above data is broken down by jurisdiction.  Of the 919
authorized intercepts, 340 (37%) were federal.  New York State had 197,
New Jersey 111, Florida 80, and Pennsylvania 77.  The remaining 114
intercepts were divided among 18 states, none of which had more than 17
intercepts.  During the past decade, the average number of authorized
intercepts per year has been about 780.

Individual law enforcement agencies also require internal reports.  For
example, the New York Sate Police requires that each week, the Troop or
Detail Captain prepare a report summarizing the status of all
eavesdropping activity within the unit, including the productivity and
plans for each electronic surveillance installation and a brief
synopsis of pertinent activity.  This is sent to the New York State
Police Division Headquarters Captain who prepares a report summarizing
the status of all eavesdropping installations.

One of the reasons for the significant amount of post wiretap reporting
is to provide a substantial record for legislatures when considering
whether or not to reenact or modify wiretap statutes.


3.  FISA Interceptions

Title 50 USC, Sections 1801-1811, the Foreign Intelligence Surveillance
Act (FISA) of 1978, covers electronic surveillance for foreign
intelligence purposes (including counterintelligence and
counterterrorism).  It governs wire and electronic communications sent
by or intended to be received by United States persons (citizens,
aliens lawfully admitted for permanent residence, corporations, and
associations of U.S. persons) who are in the U.S. when there is a
reasonable expectation of privacy and a warrant would be required for
law enforcement purposes; nonconsensual wire intercepts that are
implemented within the U.S.; and radio intercepts when the sender and
all receivers are in the U.S. and a warrant would be required for law
enforcement purposes.  It does not cover intercepts of U.S. persons who
are overseas (unless the communications are with a U.S. person who is
inside the U.S.).  Electronic surveillance conducted under FISA is
classified.

FISA authorizes electronic surveillance of foreign powers and agents of
foreign powers for foreign intelligence purposes.  Normally, a court
order is required to implement a wiretap under FISA.  There are,
however, two exceptions.  The first is when the communications are
exclusively between or among foreign powers or involve technical
intelligence other than spoken communications from a location under the
open and exclusive control of a foreign power; there is no substantial
risk that the surveillance will acquire the communications to or from a
U.S.person; and proposed minimization procedures meet the requirements
set forth by the law.  Under those conditions, authorization can be
granted by the President through the Attorney General for a period up
to one year.  The second is following a declaration of war by
Congress.  Then the President, though the Attorney General, can
authorize electronic surveillance for foreign intelligence purposes
without a court order for up to 15 days.

Orders for wiretaps are granted by a special court established by
FISA.  The court consists of seven district court judges appointed by
the Chief Justice of the United States.  Judges serve seven-year
terms.

3.1  Application for a Court Order

Applications for a court order are made by Federal officers and require
approval by the Attorney General.  Each application must include:

  (1) the Federal officer making the application;

  (2) the Attorney General's approval;

  (3) the target of the electronic surveillance;

  (4) justification that the target is a foreign power or agent of a
      foreign power (except no U.S person can be considered a foreign power
      or agent thereof solely based on activities protected by the First
      Amendment) and that the facilities or places where the surveillance
      is be directed will be used by the same;
 
  (5) the proposed minimization procedures, which must meet certain
      requirements to protect the privacy of U.S. persons;

  (6) the nature of the information sought and type of communications
      subjected to surveillance;

  (7) certification(s) by the Assistant to the President for National
      Security Affairs or other high-level official in the area of
      national security or defense (Presidential appointee subject to
      Senate confirmation) that the information sought is foreign
      intelligence information and that such information cannot
      reasonably be obtained by normal investigative methods;

  (8) the means by which the surveillance will be effected;

  (9) the facts concerning all previous applications involving the same
      persons, facilities, or places;

 (10) the period of time for the interception (maximum 90 days or,
      when the target is a foreign power, one year);

 (11) coverage of all surveillance devices to be employed and the
      minimization procedures applying to each.

Some of the above information can be omitted when the target is a
foreign power.  

Within the FBI, the process of applying for a court order under FISA is
as exacting and subject to review as under Title III.  The main
differences are that under FISA, the FBI Intelligence Division is
involved rather than the Criminal Investigative Division, the DOJ
Office of Intelligence Policy and Review (OIPR) is involved rather than
either the U.S. Attorney's Office or the DOJ Criminal Division, and the
application is approved by the Attorney General (or Acting Attorney
General) rather than by a lower DOJ official.

3.2  Issuance of a Court Order

Before a judge can approve an application, the judge must determine
that the authorizations are valid; that there is probable cause to
believe that the target of the electronic surveillance is a foreign
power or agent of a foreign power and that the facilities or places
where the surveillance is be directed will be used by the same; and
that the proposed minimization procedures meet the requirements set
forth in the law.  If the judge approves the application, an order is
issued specifying the relevant information from the application and
directing the communication carrier, landlord, custodian, or other
specified person to furnish all necessary information, facilities, and
technical assistance and to properly maintain under security procedures
any records relating to the surveillance.

3.3  Emergencies

In an emergency situation, the Attorney General or designee can
authorize the use of electronic surveillance provided the judge is
notified at the time and an application is made to the judge within 24
hours.  If such application is not obtained, then the judge notifies
any U.S. persons named in the application or subject to the
surveillance, though such notification can be postponed or forgone upon
showing of good cause.

3.4  Use of Intercepted Communications as Evidence

Like Title III, FISA places strict controls on what information can be
acquired through electronic surveillance and how such information can
be used.  No information can be disclosed for law enforcement purposes
except with the proviso that it may only be used in a criminal
proceedings under advance authorization from the Attorney General.  If
the government intends to use such information in court, then the
aggrieved person must be notified in advance.  The person may move to
suppress the evidence.

3.5  Reports

Each year, the Attorney General must give the Administrative Office of
the United States Courts (AO) a report of the number of FISA
applications and the number of orders and extensions granted, modified,
or denied.  In 1992, there were 484 orders.  Since 1979, there has been
an average of a little over 500 FISA orders per year.

Because intercepts conducted under FISA are classified, detailed
information analogous to that required under Title III is not reported
to the AO, nor made available to the public.  However, records of
Attorney General certifications, applications, and orders granted must
be held for at least 10 years, and the Attorney General must inform two
Congressional oversight committees of all surveillance activity on a
semiannual basis.  These committees are the House Permanent Select
Committee on Intelligence and the Senate Select Committee on
Intelligence.


Acknowledgements

We are grateful to Geoffrey Greiveldinger for many helpful suggestions
on an earlier draft of this report.

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