  Military Use of Infrared Radars Technology to Assist Civilian
                   Law Enforcement Agencies


T h e D ep artm en t o f D efense has statutory authority to assist civilian law enforcem ent agencies to
     id en tify o r confirm suspected illegal drug production w ithin structures located on private
     p ro p erty by p ro v iding them w ith aerial reconnaissance that uses Forw ard Looking Infrared
     R ad ars technology.


                                                                                February 19, 1991

                M   em orandum        O   p in io n fo r t h e   G   eneral   Coun sel
                                   Depa rtm      ent o f   D   efen se



   This memorandum is in response to your request for our opinion whether,
under existing statutory authority, the Department of Defense may assist
civilian law enforcement agencies to identify or confirm suspected illegal
drug production within structures located on private property by providing
them with aerial reconnaissance that uses Forward Looking Infrared Radars
technology. We conclude that such assistance is authorized by 10 U.S.C. §
374(b)(2)(B), and not prohibited by 10 U.S.C. § 375.

                                                    I.


    Forward Looking Infrared Radars (“FLIR”) is a passive technology that
detects infrared radiation generated by heat-emitting objects. Infrared rays
are received by the FLIR system, electronically processed, and projected on
a screen as a visual image in the shape o f the object that is emitting the heat.
The warm er the object, the brighter the image of the object appears. See
U nited States v. Sanchez , 829 F.2d 757, 759 (9th Cir. 1987); United States v.
K ilgu sy 571 F.2d 508, 509 (9th Cir. 1978). FLIR is not an x-ray technology.
We have been informed that it cannot provide information concerning the
interior o f an object or structure. It detects only heat emanating from sur­
faces that are directly exposed to the FLIR system. Thus, for example, if
there were heat-producing objects within a building, FLIR could detect that
m ore infrared radiation was being emitted from the building’s roof than if
the building were empty, but the system could not identify the shapes of
                                                   36
heat-emitting objects located within the structure. Nor could the system
identify the source of the heat or the precise location of the heat source
within the structure.
   Law enforcement agencies believe that FLIR technology can be useful in
identifying buildings that house marijuana crops, or methamphetamine or
other drug processing laboratories. In particular, FLIR can aid law enforce­
ment officials in establishing probable cause that criminal activity is ongoing
within a particular building by determining whether the building is radiating
unusually large amounts of heat (due to the use of high intensity lighting or
combustion generators) or unusually small amounts of heat (due to heavy
insulation). Recently, therefore, federal and state law enforcement agencies
have requested that military aircraft equipped with FLIR fly over suspect
buildings on private lands and produce infrared images of those structures.
   The Department of Defense (“DoD”) has informed us of three requests
for assistance that present the question whether such military assistance is
authorized. The Drug Enforcement Administration (“DEA”) has asked the
Army to conduct infrared imaging of a bam on private land in which the
DEA suspects that marijuana is being cultivated. Second, a law enforcement
agency has requested that an Army flight crew conduct a training mission
over certain private lands and buildings in the vicinity of Wichita, Kansas,
using an Army helicopter equipped with FLIR, to identity suspected illegal
marijuana cultivation. And third, the DEA has asked that the Army under­
take flights in OH-58D helicopters equipped with FLIR, at a height o f at
least 500 feet above ground, to identify dwellings and other structures on
private land in Arizona that the DEA suspects contain methamphetamine
laboratories. The requesting agencies maintain that the Defense Department
has the authority to provide the requested assistance under the provisions of
10 U.S.C. §§ 371-378, which are designed to promote cooperation between
military personnel and civilian law enforcement officials.

                                      II.

    Chapter 18 of title 10, which was enacted by Congress in 1981 and sub­
sequently amended in 1988 and 1989, authorizes DoD to provide several
forms of assistance to civilian law enforcement officials. Sections 371 through
373 permit the Secretary of Defense to provide these officials with informa­
tion collected during training missions; equipment or facilities needed for
law enforcement purposes; and training or advice relevant to equipment that
is provided. Section 374 authorizes the Secretary to make DoD personnel
available for the operation and maintenance of equipment in connection with
a limited number of law enforcement purposes. Each of these authorizations
is subject to the limitations in section 375 that the Secretary o f Defense
prevent “direct participation by a member of the Army, Navy, Air Force, or



                                      37
Marine Corps in a search, seizure, arrest, or other similar activity.” Id. § 375.1
   We believe it is clear from the language and legislative history of sections
371 through 374 that FLIR surveillance is authorized by those sections,
subject to the restrictions of section 375.2 Section 372 permits the Secretary
of Defense to make available to any federal, state or local law enforcement
official “any equipment” for law enforcement purposes, and obviously FLIR
constitutes “equipment.” Section 374, as amended, allows DoD personnel to
operate such equipment for the purpose o f “aerial reconnaissance,” which is
precisely what is contemplated in the requests that have been made. 10
U.S.C. § 374(b)(2)(B).3 The normal meaning of the term “reconnaissance” is
“an exploratory or preliminary survey, inspection, or examination made to
gain information.” Webster's Third New International Dictionary 1897 (1986).
FLIR surveillance from aircraft is clearly “aerial reconnaissance,” so de­
fined. The only limitation on aerial reconnaissance even suggested by the
legislative history is that it should “be used for reconnaissance of property
and not for surveillance of persons.” H.R. Conf. Rep. No. 989, 100th Cong.,
2d Sess. 451 (1988) (“1988 Conference Report”). Here, of course, the pro­
posed reconnaissance is of property, not persons. We conclude, therefore,

   'T h e scope of section 375 is itself restricted by 10 U.S.C. § 378, which states that “[n]othing in this
chapter shall be construed to limit the authority of the executive branch in the use o f military personnel
or equipm ent for civilian law enforcement purposes beyond that provided by law before D ecember 1,
 1981.” Thus, if FLIR surveillance o f private buildings would not have been prohibited by the Posse
C om itatus Act, 18 U.S.C. § 1385, before 1981, section 375 does not proscribe such surveillance. See
infra note 16.
   2All parties who have reviewed the requests for DoD assistance that are at issue here appear to agree
with this conclusion. Memorandum for Terrence O’Donnell, General Counsel, Department of Defense,
from Robert M . Sm ith, Jr., at 32-33 (Sept. 19,1980) (“Smith Memorandum”); Memorandum for Office of
the Deputy C h ief of Staff for Operations and Plans, from Patrick J. Parrish, Assistant to the General
Counsel, D epartm ent o f the Army at 1 (Sept. 17, 1990) (“Parrish M emorandum” ); M emorandum for
Joint C hiefs o f Staff, from Lt. Col. C.W. Hoffman, Jr., Deputy LLC at 1 (Aug. 14, 1990) (“Hoffman
M em orandum ” ).
   3O riginally, section 374 authorized D oD personnel to operate equipment “only to the extent the equip­
m ent is used for m onitoring and communicating the movement of air and sea traffic," and in certain
em ergency circum stances. Department o f Defense Authorization Act, 1982, Pub. L. No. 97-86, tit. IX,
§ 905(a)(1), 95 Stat. 1099, 1115 (1981). At the time, Congress believed these were the “primary type[s]
o f assistance sought and needed by Federal drug enforcement agencies.” H.R. Conf. Rep. No. 311, 97th
Cong., 1st Sess. 120 (1981) (“ 1981 Conference Report”).
   W hen it added the authority for m ilitary aerial reconnaissance assistance in 1988, Congress intended
to perm it m ilitary assistance not only in connection with the interdiction of drugs bound for the United
States from foreign countries, but also in connection with the eradication of dom estically produced
narcotics. Several witnesses before the House and Senate Armed Services Committees testified that
DoD assistance in the domestic “drug w ar” was in high priority. See The Role o f the M ilitary in Drug
Interdiction: Joint Hearings Before the House and Senate Armed Services Committees, 100th Cong..
2d Sess. 187 (1988) (statement of Larry L. Orton, Special Agent in Charge, El Paso Intelligence Center,
Drug E nforcem ent Agency) ("We further believe that the National Guard [should] help us in the role
that we have here domestically in the United States, and that is the eradication o f domestically grown
m arijuana in the national fo rce .. .. We actually need people to go in, fly over them and locate them,
and then go into the patches to eradicate."); id. at 242 (statement of Don Siegelman, Attorney General
o f A labam a) (“ M ilitary equipment and certain personnel should be made available, under specified
conditions, to assist civilian authorities conduct air and land marijuana spotting and eradication. M ili­
tary helicopters and pilots could make a significant contribution to the systematic aerial surveying of
suspected m arijuana growing areas.” ); id. at 257 (statem ent of Edward Koch, M ayor of New York, New
York) (“I believe that those helicopters should be flying over identifying the marijuana fields. . . . Then
you notify the local cops, and the cops go in and make the arrest.”).

                                                    38
that FLIR surveillance of buildings on private property is authorized aerial
reconnaissance under sections 371-374, subject only to the restrictions set
forth in section 375.4

                                                 III.

   Section 375 requires the Secretary of Defense to prescribe regulations
ensuring that activity undertaken pursuant to sections 371 to 374 does not
result in “direct participation by a member of the Army, Navy, Air Force, or
Marine Corps in a search, seizure, arrest, or other similar activity.” 10
U.S.C. § 375. The Secretary has promulgated regulations, based upon an
earlier version of the statute, that prohibit military personnel from conduct­
ing “[a] search or seizure.” 32 C.F.R. § 213.10(a)(3).5 We understand DoD
to take the position that the term “search” in the regulations is intended to
have the same meaning as does the statutory term “search,” and we assume
for purposes of this opinion that this is correct.
   DoD has assumed that the statutory term “search” was intended to be
coextensive with the same term in the Fourth Amendment and thus that the
applicability of the section 375 prohibition to the assistance requested here
turns on whether the FLIR surveillance constitutes a “search” within the
meaning of the Fourth Amendment.6 Proceeding on this assumption, DoD
has concluded that FLIR surveillance is a “search,” and therefore that sec­
tion 375 prohibits the military from providing the FLIR surveillance assistance
to civilian law enforcement agencies. We conclude from the language, struc­
ture, and legislative history of section 375 that, contrary to DoD’s assumption,
the meaning of the term “search” was not intended to be coextensive with
the meaning of the same term in the Fourth Amendment. Instead, when Con­
gress used the term “search” in section 375, it intended that the term encompass
at most only searches involving physical contact with civilians or their

  4 Section 371 authorizes the Secretary of Defense to provide to civilian law enforcement officials “any
information collected during the normal course o f military training or operations that may be relevant
to a violation o f any Federal or State law.” DoD’s provision of FLIR surveillance information obtained
during training missions in the vicinity of Wichita, Kansas, would thus appear to be separately autho­
rized by section 371 if the requested FLIR surveillance were conducted in'the “normal course of military
training."
  ! The regulations promulgated by the Department of Defense state'
      Except as otherwise provided in this enclosure, the prohibition on use of military personnel
      “as a posse comitatus or otherwise to execute the laws" prohibits the following forms of
      direct assistance:
             (i) Interdiction of a vehicle, vessel, aircraft or other similar activity.
             (ii) A search or seizure.
             (iii)An arrest, stop and frisk, or similar activity.
             (iv) Use of military personnel for surveillance or pursuit o f individuals, or as in­
           formants, undercover agents, investigators, or interrogators.
32 C.F.R. § 213.10(a)(3) (1991). These regulations were promulgated after chapter 18 was enacted in
1981, but they have not been amended to achieve consistency with the statutory changes enacted in 1988
and 1989. For example, subsection (i) of the regulations includes language that no longer appears in 10
U.S.C. § 375.
  ‘ Smith Memorandum at 3, 32-38; accord Parrish Memorandum at 1; contra Hoffman M emorandum at
2, supra.

                                                 39
property, and perhaps only searches involving physical contact that are likely to
result in a direct confrontation between military personnel and civilians.

                                                    A.

   There is no reason to assume, as a threshold matter, that the meaning of
the term “search” in section 375 is coextensive with that of the same word
in the Fourth Amendment. “ [0 ]f course words may be used in a statute in a
different sense from that in which they are used in the Constitution.” Lamar
v. U nited States, 240 U.S. 60, 65 (1916); see also Verlinden B.V. v. Central
Bank o f N igeria , 461 U.S. 480, 494-95 (1983) (meaning of “arising under”
in Article III, Section 2 differs from that of the same phrase in 28 U.S.C. §
 1331); Towne v. Eisner , 245 U.S. 418, 425 (1918) (“[I]t is not necessarily
true that income means the same thing in the Constitution and the [Income
Tax] Act.”). The term “search” has acquired a specialized meaning in Fourth
Amendment jurisprudence, in light of the Amendment’s expansive purpose
to protect all reasonable expectations of privacy. That specialized definition
clearly encompasses activity in which there is no physical contact with or
intrusion into private property, such as electronic wiretapping. Katz v. United
States, 389 U.S. 347 (1967).
   In common parlance, however, the term usually connotes at least some
amount of physical contact or interference. Indeed, Justice Brandeis con­
ceded in his dissenting opinion in Olm stead v. United States, 277 U.S. 438
(1928), which foreshadowed the Court’s decision in Katz overruling Olmstead,
that the “ordinary meaning” of “search” would encompass only activity in­
volving a physical trespass. Id. at 476-78 (Brandeis, J., dissenting). Although
Justice Brandeis was ultimately unsuccessful in persuading his colleagues of
his substantive position, the most that he could say about their construction
of the term “search” was that it was “unduly literal.”7 The “ordinary mean­
ing” o f “search” relied upon by the Court and recited by Justice Brandeis in
Olm stead is frequently that intended by Congress. A number of statutes con­
cerning searches by law enforcement officials, for example, seem to assume that
a “search” involves some physical contact between law enforcement personnel
and civilians.8 It should not be presumed, therefore, that the term “search” in
section 375 is coextensive with the same term in the Fourth Amendment.
  ’ It is evident from his opinion that Justice Brandeis did not use the phrase “ unduly literal" to suggest
that the m ajority was mistaken as to the ordinary meaning of the term “ search.” His only point was that
adoption o f the “ordinary meaning” o f the term was inappropriate given the broad privacy protection
purpose o f the Fourth Amendment.
  ’ See, e.g., 7 U.S.C. § 164a (authorizing Department o f Agriculture employees “to stop and, without
warrant, to inspect, search, and exam ine such person, vehicle, receptacle, boat, ship, or vessel” ); 18
U .S.C . § 913 (subjecting to prosecution “[wjhoever falsely represents himself to be an officer, agent, or
em ployee o f the United States, and in such assumed character arrests or detains any person or in any
m anner searches the person, buildings, or other property of any person” ); id. § 2231 (subjecting to
prosecution “ (w ]hoever forcibly assaults, resists, opposes, prevents, impedes, intimidates, or interferes
with any person authorized to serve o r execute search warrants or to make searches and seizures"); id.

                                                Continued

                                                    40
    The context in which the word “search” appears in section 375 suggests
that Congress indeed may have intended the term to refer only to searches
involving physical contact. Section 375 employs the term “search” in asso­
ciation with “seizure” and “arrest,” terms which contemplate some physical
contact with persons or property.9 If one invokes the common sense maxim
noscitur a sociis, “[w]here any particular word is obscure or o f doubtful
meaning, taken by itself its obscurity or doubt may be removed by reference
to associate words,” Virginia v. Tennessee, 148 U.S. 503, 519 (1893), it would
appear that Congress intended for the term “search” in title 10 to have the
narrow, “ordinary meaning,” rather than the meaning ascribed to the term in
the Fourth Amendment. This suggestion is reinforced by the fact that Con­
gress extended the prohibition in section 375 also to “other sim ilar
activities],” that is, to other activities similar to searches, seizures, and ar­
rests. It is apparent from this phrase that Congress regarded searches, seizures,
and arrests as similar activities.10 Apart from the obvious fact that these are
all law enforcement activities, one of the fundamental similarities of these
activities is that each entails some amount of physical contact.
   The intent of Congress in section 375 to prohibit only searches involving
physical contact is particularly evident in the original version of section 375.
As enacted in 1981, section 375 forbade direct participation by DoD person­
nel “in an interdiction of a vessel or aircraft, a search and seizure, arrest, or
other similar activity.” Pub. L. No. 97-86, tit. IX, § 905(a)(1), 95 Stat. 1099
1116 (1981) (emphasis added). The coupling of “search” and “seizure”
through use of the conjunctive “and,” and the reference to the two as a
single event (i.e., “a search and seizure”), strongly suggests that Congress
was referring to searches of persons or objects that had been seized and thus
were in the custody of law enforcement officers. Searches of seized persons
or objects almost always involve physical contact.11
   '(....continued)
§ 2232 (distinguishing between “searches" and "electronic surveillance” and prohibiting “ Physical Inter­
ference With Search” ); 33 U.S.C § 383 (“The commander and crew of any merchant vessel o f the U nited
States . . . may oppose and defend against any aggression, search, restraint, depredation, or seizure, which
shall be attempted upon such vessel          .”).
   ’ To “seize” is to “ take hold of suddenly or forcibly" or “to take possession of by force or at will."
Random House Dictionary o f the English Language 1734 (1987). In the law, a “seizure” generally
requires “an intentional acquisition of physical control." Brower v. County o f Inyo, 489 U S 593, 596
(1989). “ Arrest” is most commonly defined as “ the act of stopping or restraining (as from further
m otion).” Webster's Third New International Dictionary 121 (1986) The traditional meaning of “ar­
rest" in the legal context is the seizure of a person which “eventuate[s] in a trip to the station house and
prosecution for crim e.” Terry v. Ohio, 392 U.S. 1, 16 (1968). See also Douglas v. Buder, 412 U S. 430,
431-32 (1973); Cupp v. Murphy, 412 U S 291, 294 n 1 (1973). Both arrests and seizures thus virtually
always entail physical contact.
   l0It is possible to read the catch-all phrase “other similar activ ities]” to include any activity similar to
searches, similar to seizures, or similar to arrests, in which event no inference need be drawn as to
whether Congress regarded searches, seizures, and arrests as themselves similar to each other. This
would be a natural reading of the phrase, however, only if the enumerated activities had nothing in
common.
   " The inference that Congress was concerned only with searches that entail some physical contact is
strengthened by the inclusion of “ search and seizure" in a series of terms with “interdiction” and "ar­
rest,” both o f which also generally entail physical contact. See supra p. 41


                                                     41
   Although Congress amended section 375 in 1989, so that it now prohibits
participation in a “search, seizure, arrest, or similar activity,” there is no
indication that by deleting the word “and,” Congress intended to signal a depar­
ture from the statute’s original purpose. See H.R. Conf. Rep. No. 331, 101st
Cong., 1st Sess. 654 (1989). The 1989 amendment merely clarifies the section
so as to prohibit military personnel from participating in searches entailing
physical contact, even if they will not involve or lead ultimately to seizures.

                                                   B.

                                                    1.

   The legislative history of chapter 18 confirms that Congress intended in
section 375 to prohibit at most searches by the military that entail physical
contact with civilians or their property, and perhaps only such searches that
are likely to result in direct confrontation between military personnel and
civilians. The history of section 375 actually begins with the Posse Comita-
tus Act, 18 U.S.C. § 1385, which governed military involvement in law
enforcement activity prior to enactment o f chapter 18 in 1981.12 The Posse
Comitatus Act was adopted in 1878 in response to objections from southern
States to United States Army participation in civilian law enforcement dur­
ing Reconstruction. In the one hundred years immediately following its
enactment, the Posse Comitatus Act was rarely the subject of litigation. To
date, few courts have attempted to define the contours of the Act, and there
apparently has never been a prosecution under the Act. See Posse Comitatus
A ct, H earings on H.R. 3519 Before the Subcomm. on Crime o f the House
Comm, on the Judiciary, 97th Cong., 1st Sess. 21 (1981) (statement of Ed­
ward S.G. Dennis, Jr., Department of Justice) ("Posse Comitatus Hearings").
By 1948, the Posse Comitatus Act was characterized by one court as an
“obscure and all-but-forgotten statute.” Chandler v. United States, 171 F.2d
921, 936 (1st Cir. 1948), cert, denied , 336 U.S. 918 (1949).
   The courts that confronted issues under the Posse Comitatus Act before
1981 did not interpret the Act uniformly. Some understood the Act as a
broad and absolute prohibition against virtually any military participation in
civilian law enforcement activity. In two cases arising from the 1973 fed­
eral occupation of Wounded Knee, South Dakota, for example, the courts
concluded that the mere provision of tactical advice by a military officer, if
it were subsequently acted upon by civilians, would be unlawful. United
States v. Jaramillo, 380 F. Supp. 1375, 1381 (D.S.D. 1974), appeal dism issed,


  1: The Posse Com itatus Act states:
          W hoever, except in cases and under circumstances expressly authorized by the Constitu­
       tion o r Act o f Congress, willfully uses any part o f the Army or the Air Force as a posse
       com itatus or otherw ise to execute the laws shall be fined not more than $10,000 or im pris­
       oned not m ore than two years, or both.
18 U.S.C. § 1385.

                                                   42
510 F.2d 808 (8th Cir. 1975); United States v. Banks, 383 F. Supp. 368, 375
(D.S.D. 1974). Another court held under the Federal Tort Claims Act that
the use of an Air Force helicopter and its personnel to aid in a search for a
nonmilitary prison escapee was forbidden by the Posse Comitatus Act. The
court emphasized that “[t]he innocence and harmlessness of the particular
use of the Air Force in the present case [and] the dissimilarity of that use to
the uses that occasioned the enactment . . . are irrelevant to the operation of
a statute that is absolute in its command and explicit in its exceptions.”
 Wrynn v. United State, 200 F. Supp. 457, 465 (E.D.N.Y. 1961).
    Other courts, however, concluded that the Posse Comitatus Act permitted
military personnel to offer certain forms of “passive” or “nonauthoritarian”
assistance to civilians. In another Wounded Knee case, the court interpreted
the Act to prohibit the military from “actively performing direct law en­
forcement duties,” but to allow a “passive role which might indirectly aid
[law enforcement].” United States v. Red Feather, 392 F. Supp. 916, 924-25
(D.S.D. 1975). This court concluded that military involvement in the arrest
of a person, seizure of evidence, search of a person, or search of a building
constituted impermissible “direct” aid, but that tactical advice, training, and
aerial photographic reconnaissance flights were “indirect” assistance permit­
ted by the Act. Id.
    A second court concluded after transfer of the Red Feather case that the
Posse Comitatus Act prohibited only military activity “which is regulatory,
prescriptive or compulsory in nature, and causes the citizens to be presently
or prospectively subject to regulations, proscriptions, or compulsions im­
posed by military authority.” United States v. McArthur, 419 F. Supp. 186,
 194 (D.N.D. 1975), a ff’d sub nom., United States v. Casper, 541 F.2d 1275
(8th Cir. 1976), cert, denied, 430 U.S. 970 (1977). The court believed that
the Act did not outlaw “the borrowing of highly skilled personnel, like pilots
and highly technical equipment like aircraft and cameras, for a specific,
limited, temporary purpose.” Id. This Office, in 1978, endorsed the com­
mon points of the analyses in Red Feather and McArthur, concluding that
military assistance in civilian law enforcement does not violate the Posse
Comitatus Act where “there is no contact with civilian targets of law en­
forcement, no actual or potential use of military force, and no military control
over the actions of civilian officials.” Letter for Deanne Siemer, General Coun­
sel, Department of Defense, from Mary Lawton, Deputy Assistant Attorney
General, Office of Legal Counsel at 13 (Mar. 24, 1978) (“Lawton Letter”).
    In the wake of this series of decisions, there understandably was substan­
tial confusion over the kinds of assistance that the military could provide to
civilian law enforcement officials.

                                      2   .
   Congress addressed the confusion that had arisen and clarified the bound­
aries o f perm issible DoD law enforcem ent activity in 1981 through
                                      43
 amendments to chapter 18. H.R. Rep. No. 71, 97th Cong., 1st Sess., pt. 2, at
 3 (1981) (“ 1981 House Report”); S. Rep. No. 58, 97th Cong., 1st Sess. 148
 (1981). It is evident from the legislative history of these amendments that
 Congress intended to codify the distinction — articulated by the district
court in United States v. R ed Feather — between “indirect passive” assis­
tance and “direct active” involvement in law enforcement activity. Edward
D ennis, testifying on b eh alf of the Departm ent of Justice, stated the
D epartm ent’s view that “the principle which is put forth in the statutes is
that the armed services would be called upon to lend indirect and passive
forms o f assistance to civilian law enforcement.” Posse Comitatus Hear­
ings , at 21. An expert on military-civilian relations, Professor Christopher
Pyle, objected strenuously to the Red Feather analysis, but acknowledged
that “[i]t is not difficult to see how the proposals currently before the Sub­
committee build upon this opinion.” Id. at 42. And Rear Admiral Donald
Thompson of the Coast Guard reported that the Navy relied on the Wounded
Knee cases to “permit[] aerial surveillance or photo-reconnaissance mis­
sions in support o f law enforcement activities on a not-to-interfere basis.”
Id. at 49.
    The committee reports from the House Judiciary Committee and the Con­
ference Committee are relatively clear that Congress intended to adopt the
R ed Feather passive-active distinction. The committee report on the House
bill, from which the authority granted in section 374 derives, rejected the
absolutist view of the Posse Comitatus Act taken by the courts in United
States v. Jaram illo and U nited States v. Banks, stating that those decisions
“serve to illustrate the confusion regarding the Act and the problems that
result when it is too mechanically applied.” 1981 House Report, at 6. The
House committee referred more favorably to the conclusion of the Red Feather
court that only “the direct active use o f Army or Air Force personnel” was
prohibited, id., and the Conference Committee eventually provided in sec­
tion 375 for restrictions only “on the direct participation of military personnel
in law enforcement activities.” 1981 Conference Report at 121.
    Significantly, Congress understood R ed Feather to prohibit only activity
that entailed direct, physical confrontation between military personnel and
civilians. During the hearings, Representative Hughes, Chairman o f the Sub­
committee on Crime, observed to William H. Taft IV, General Counsel of
the Department of Defense:

       I can understand where you might have to have military per­
       sonnel, actually operate [in a law enforcement capacity] under
       given circumstances. I understand that. But that is a long
       way from giving them the authority to make an arrest or to
       make a seizure.
        An assist, as opposed to a military person making an arrest
       or participating in a seizure is an important distinction.

                                       44
Posse Comitatus Hearings, at 28. During the same exchange, Mr. Taft en­
dorsed that prohibition on direct participation by military personnel in arrests
or seizures, and presented his view of the passive-active principle: “[I]t is
the arrests and the seizures, and active — putting, really, into a confronta­
tion, an immediate confrontation, the military and a violator o f a civilian
statute, that causes us the greatest concern.” Id. at 30 (emphasis added).13
    Congress’ concern with confrontation between military personnel and ci­
vilians is also apparent from the discussions over the provisions of the original
section 374(c). That section authorized the use of military personnel to
operate equipment outside the land area of the United States only in certain
emergencies where the Attorney General and the Secretary of Defense jointly
determine that an emergency exists. These procedural safeguards were in­
corporated because “[t]he conferees were concerned that [the] use o f military
personnel in such operations had the potential fo r placing such personnel in
confrontational situations." 1981 Conference Report at 120 (emphasis added).
    In sum, in codifying the Red Feather passive-active participation distinc­
tion, Congress “maximize[d] the degree of cooperation between the military
and civilian law enforcement,” 1981 House Report at 3, while carefully pre­
venting the direct, physical confrontation between military personnel and
civilians which it believed would “fundamentally alter the nature of the
relationship between the military and civilian society.” Id. at l l . 14

                                                    3.

   In 1988, Congress enacted amendments to chapter 18 which further un­
derscore that the purpose of section 375 was to codify the R ed Feather
distinction between “passive” and “active” assistance and thus to prohibit
direct interface between military forces and civilians. National Defense
Authorization Act, Fiscal Year 1989, Pub. L. No. 100-456, § 1104, 102 Stat.
1918, 2045 (1988). Specifically, Congress deleted the ban in section 375 on
participation in “an interdiction of a vessel or aircraft,” because that phrase
had been understood to prohibit activities which did not involve physical
confrontation between the military and civilians. The Conference Report
explains:

          The conferees deleted the term “interdiction of a vessel or
          aircraft,” which is set forth in current law, because the term
          “interdiction ” has acquired a meaning that includes detection
          and monitoring as well as a physical interference with the

  13This colloquy caused Representative Hughes to propose language, which was eventually incorpo­
rated into section 374(b), that allows DoD personnel to operate or assist in operating equipm ent for law
enforcem ent purposes. Id. at 29.
  14Some activities prohibited under the Red Feather analysis, such as searches o f buildings and seizures
of evidence, do not necessarily entail confrontations with civilians. To the extent that such searches are
prohibited under section 375, this reflects Congress’ concern that in carrying out such activities, military
personnel likely would be placed in a confrontational posture with civilians.

                                                   45
          m ovem ent o f a vessel o r aircraft.The conferees emphasize,
          however, that they do not intend by this action to authorize
          military personnel to interrupt the passage of a vessel or air­
          craft except as otherwise authorized by law.

1988 Conference Report at 452 (1988) (emphasis added).

     As part of the 1988 revision, Congress also amended section 374 to au­
 thorize DoD personnel to operate equipment outside the United States for
 the purpose of transporting civilian law enforcement officials. 10 U.S.C. §
 372(b). This authority, however, was expressly made subject to joint ap­
 proval by the Secretary of Defense, the Attorney General, and the Secretary
 of State “because of the potential fo r involving D O D personnel in a direct
 law enforcement confrontation, even though their role is designed for logis­
 tical support.” 1988 Conference Report at 452 (emphasis added). Finally, a
 new subsection (c) of section 374 was added to permit the Secretary of
 Defense to make DoD personnel available to civilian law enforcement offi­
 cials for other purposes, but “only to the extent that such support does not
 involve direct participation by such personnel in a civilian law enforcement
 operation.” Id. § 374(c). In a telling explanation of how Congress under­
 stood the prohibition in subsection 374(c) on “direct participation . . . in a
civilian law enforcement operation,” the Conference Report stated that “[t]o
the extent that transportation of law enforcement officials or use of military
officials does not reasonably raise the possibility o f a law enforcement con­
fro n ta tio n , such assistance may be provided in the United States under
 subsection (c).” 1988 Conference Report at 452 (emphasis added).15
    Accordingly, we conclude that Congress intended section 375 to prohibit
 at most military participation in searches involving physical contact with civil­
 ians or their property, and perhaps only such searches that are likely to result in
 direct, physical confrontation between military personnel and civilians.16




   15 Tw o recent opinions o f this Office have concluded, based largely on this legislative history, that
Congress intended in section 375 to bar only the exercise of military authority in contexts where there
are likely to be direct confrontations with civilians. Use o f Navy Drug-Detecting Dogs by Civilian
Postal Inspectors, 13 Op. O.L.C. 312 (1989); Use o f Department o f Defense Drug-Detecting Dogs to
A id in Civilian Law Enforcement, 13 Op. O.L.C. 185 (1989).
   '‘ Because FLIR aerial reconnaissance is authorized by section 374 and not prohibited by section 375, it
cannot be prohibited by the Posse Com itatus Act. That Act, by term s, does not apply to activities “ex­
pressly authorized by the Constitution or Act of Congress.” 18 U.S.C. § 1385. For the same reason, we
need not consider whether FLIR surveillance would otherwise be permitted by the Posse Comitatus Act,
and thus excepted from the prohibitions of section 375 by 10 U.S.C. § 378. As noted, however, this
Office concluded in 1978 that the Posse Comitatus Act does not bar the use o f military personnel in
situations where “ [t]here is no contact with civilian targets of law enforcement, no actual or potential
use o f m ilitary force, and no military control over actions of civilian officials." Lawton Letter at 13.
Thus, there is a substantial argument th at FLIR surveillance to assist civilian law enforcement officials
would be perm itted by the Posse Com itatus Act even in the absence of section 374, and therefore could
not be prohibited by section 375.

                                                  46
                                                 IV.

   DoD’s principal argument that section 375 prohibits FLIR surveillance is
that the term “search” in section 375 is coextensive with the term “search”
in the Fourth Amendment. This argument rests on the unsupported assertion
that the “usual” meaning of “search” is that ascribed to the term in the
Fourth Amendment, see Smith Memorandum at 34, an assertion that we re­
ject for the reasons set forth above. DoD also supports its argument with the
general statements from the legislative history that Congress sought to ‘“ reaf­
firm the traditionally strong American antipathy towards the use of the military
in the execution of civil law’” and to avoid ‘“ modification in this country’s
long tradition of separating the military from day to day involvement in the
execution and operation of the civilian laws.’” Smith Memorandum at 34
(quoting 1981 House Report at 10-11). Reliance upon Congress’ reaffirma­
tion of these traditions, however, begs the only relevant question, which is
precisely what historical paradigm Congress sought to reaffirm. As we have
shown, the text and history of the legislation amply dem onstrate that
tradition was essentially that military personnel should be excluded from
participation in activities that are likely to result in direct confrontation
with civ ilians.17
   DoD also argues that because Congress in recent years has declined to
authorize active military personnel to conduct searches of cargo, vehicles,
vessels, and aircraft at points of entry into the United States, section 375
cannot be interpreted to prohibit only activity that would result in confronta­
tion between military personnel and civilians. Smith Memorandum at 34.
We would not draw any inference about the meaning of the statute from
Congress’ inaction on these proposals. See Pension Benefit Guaranty Corp.
v. The LTV Corp., 496 U.S. 633, 650 (1990); United States v. Wise, 370 U.S.
405, 411 (1962). In any event, an interpretation of section 375 that pre­
cluded border searches could well be consistent with our analysis, because
such searches generally would require use of the military in circumstances
likely to result in physical contact or in confrontations with civilians.
   Finally, if DoD’s interpretation of section 375 were correct, then section
375 would prohibit much of the assistance to civilian law enforcement that is
authorized under section 374. Section 375 forbids direct participation not only
in searches, seizures, and arrests, but also in “other similar activity.” If aerial
reconnaissance flights over private lands using FLIR technology constitute


   17 DoD acknowledges in a footnote that “[t]he Red Feather test was adopted . . . by the Congress in 10
U S C § 375,” but contends that FLIR surveillance by military personnel nonetheless would violate
section 375 because military personnel would be "actively performing direct law enforcem ent duties.”
Smith Memorandum at 35 n.106 (quoting United States v Red Feather, 392 F. Supp. 916, 925 (D S.D.
1975)). Once one concedes that Congress intended to codify in section 375 the Red Feather analysis, it
is virtually impossible to conclude that FLIR surveillance is prohibited under the section Congress
clearly understood Red Feather to prohibit at most only searches that involved physical contact with
civilians or their property And the Red Feather court even stated that aerial photographic reconnais­
sance was not “direct” assistance of the kind prohibited by the Posse Comitatus Act. 392 F Supp. at 925.

                                                 47
“searches,” then analogous activities, such as aerial reconnaissance of open
m arijuana fields using binoculars or night-vision equipment, naked eye ob­
s e rv a tio n s o f sm oke em issio n s from b u ild in g ro o fto p s, and o ther
non-trespassory means of detecting and monitoring drug smuggling or pro­
duction would constitute “other similar activities],” and thus be prohibited.
See supra at p. 41 & n.l l.18 Indeed, much of the law enforcement assistance
authorized by section 374 would be prohibited if FLIR surveillance consti­
tutes a “ search” for purposes of the statute. DoD personnel would be
forbidden, for example, from operating equipment for detection, monitoring,
and communication of the movement of air and sea traffic and from con­
ducting aerial reconnaissance. 10 U.S.C. § 374(b)(2). Congress obviously
did not intend to forbid in section 375 the activity that it authorized in
section 374. It is evident therefore that the term “search” in section 375
cannot include FLIR surveillance.

                                        CONCLUSION

   We believe that the language, structure, and history of section 375 to­
gether convincingly demonstrate that Congress intended to prohibit at most
searches by the military that entail physical contact with civilians or their
property, and perhaps only searches entailing physical contact that are likely
to result in a direct confrontation between military personnel and civilians.
Because FLIR surveillance does not constitute even a search involving physi­
cal contact with civilians or their property, we conclude that DoD personnel
are authorized by section 374(b)(2)(B) to conduct FLIR surveillance of build­
ings on private property, even assuming that the surveillance constitutes a
search for purposes of the Fourth Amendment.19

                                                           J. MICHAEL LUTTIG
                                                        Assistant Attorney General
                                                         Office o f Legal Counsel




   18 D oD apparently would confine the prohibition on “other similar activity” to Fourth Amendment
searches, and it would not construe section 373 to ban other activities permitted by section 374. Even
accepting D oD ’s assum ption that FLIR surveillance constitutes a Fourth Amendment search, however,
this sim ply is not a permissible construction of the text, because it would render the general words
“other sim ilar activity” meaningless
   19D oD has not asked us to address, and we do not address, whether FLIR surveillance constitutes a
F ourth Am endm ent search. See Smith Memorandum at 3.

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