UNITED STATES v. OAKLAND CANNABIS BUYERS’ COOPERATIVE et al.

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483 OCTOBER TERM, 2000
Syllabus
UNITED STATES v. OAKLAND CANNABIS BUYERS’
COOPERATIVE et al.
certiorari to the united states court of appeals for
the ninth circuit
No. 00–151. Argued March 28, 2001—Decided May 14, 2001
Respondent Oakland Cannabis Buyers’ Cooperative was organized to dis-
tribute marijuana to qualified patients for medical purposes. The
United States sued to enjoin the Cooperative and its executive director,
also a respondent (together, the Cooperative), under the Controlled Sub-
stances Act. The United States argued that the Cooperative’s activi-
ties violated the Act’s prohibitions on distributing, manufacturing, and
possessing with the intent to distribute or manufacture a controlled sub-
stance. The District Court enjoined the Cooperative’s activities, but
the Cooperative continued to distribute marijuana. The District Court
found the Cooperative in contempt, rejecting its defense that any distri-
butions were medically necessary. The court later rejected the Cooper-
ative’s motion to modify the injunction to permit medically necessary
distributions. The Cooperative appealed, and the Ninth Circuit re-
versed and remanded the ruling on the motion to modify the injunction.
According to the Ninth Circuit, medical necessity is a legally cognizable
defense likely applicable in the circumstances, the District Court mis-
takenly believed it had no discretion to issue an injunction more limited
in scope than the Controlled Substances Act, and the District Court
should have weighed the public interest and considered factors such as
the serious harm in depriving patients of marijuana in deciding whether
to modify the injunction.
Held:
1. There is no medical necessity exception to the Controlled Sub-
stances Act’s prohibitions on manufacturing and distributing mari-
juana. Pp. 489–495.
(a) Because that Act classifies marijuana as a schedule I controlled
substance, it provides only one express exception to the prohibitions on
manufacturing and distributing the drug: Government-approved re-
search projects. The Cooperative’s contention that a common-law med-
ical necessity defense should be written into the Act is rejected. There
is an open question whether federal courts ever have authority to recog-
nize a necessity defense not provided by statute. But that question
need not be answered to resolve the issue presented here, for the terms

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Syllabus
of the Controlled Substances Act leave no doubt that the medical neces-
sity defense is unavailable. Pp. 489–491.
(b) Under any conception of legal necessity, the defense cannot suc-
ceed when the legislature itself has made a determination of values.
Here, the Act reflects a determination that marijuana has no medical
benefits worthy of an exception (other than Government-approved re-
search). Whereas other drugs can be dispensed and prescribed for
medical use, see 21 U. S. C. § 829, the same is not true for marijuana,
which has “no currently accepted medical use” at all, § 812. This conclu-
sion is supported by the structure of the Act, which divides drugs into
five schedules, depending in part on whether a drug has a currently
accepted medical use, and then imposes restrictions according to the
schedule in which it has been placed. The Attorney General is author-
ized to include a drug in schedule I, the most restrictive schedule, only
if the drug has no currently accepted medical use. The Cooperative
errs in arguing that, because Congress, instead of the Attorney General,
placed marijuana into that schedule, marijuana can be distributed when
medically necessary. The statute treats all schedule I drugs alike, and
there is no reason why drugs that Congress placed there should be sub-
ject to fewer controls than those that the Attorney General placed there.
Also rejected is the Cooperative’s argument that a drug may be found
medically necessary for a particular patient or class even when it has
not achieved general acceptance as a medical treatment. It is clear
from the text of the Act that Congress determined that marijuana has
no medical benefits worthy of an exception granted to other drugs. The
statute expressly contemplates that many drugs have a useful medical
purpose, see § 801(1), but it includes no exception at all for any medical
use of marijuana. This Court is unwilling to view that omission as an
accident and is unable, in any event, to override a legislative determina-
tion manifest in the statute. Finally, the canon of constitutional avoid-
ance has no application here, because there is no statutory ambiguity.
Pp. 491–495.
2. The discretion that courts of equity traditionally possess in fashion-
ing relief does not serve as a basis for affirming the Ninth Circuit in
this case. To be sure, district courts properly acting as courts of equity
have discretion unless a statute clearly provides otherwise. But the
mere fact that the District Court had discretion does not suggest that
the court, when evaluating the motion, could consider any and all factors
that might relate to the public interest or the parties’ conveniences,
including medical needs. Equity courts cannot ignore Congress’ judg-
ment expressed in legislation. Their choice is whether a particular
means of enforcement should be chosen over another permissible means,

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Syllabus
not whether enforcement is preferable to no enforcement at all. To the
extent a district court considers the public interest and parties’ conven-
iences, the court is limited to evaluating how those factors are affected
by the selection of an injunction over other enforcement mechanisms.
Because the Controlled Substances Act covers even those who have
what could be termed a medical necessity, it precludes consideration of
the evidence that the Ninth Circuit deemed relevant. Pp. 495–499.
190 F. 3d 1109, reversed and remanded.
Thomas, J., delivered the opinion of the Court, in which Rehnquist,
C. J., and O’Connor, Scalia, and Kennedy, JJ., joined. Stevens, J.,
filed an opinion concurring in the judgment, in which Souter and Gins-
burg, JJ., joined, post, p. 499. Breyer, J., took no part in the consider-
ation or decision of the case.
Acting Solicitor General Underwood argued the cause
for the United States. With her on the briefs were for-
mer Solicitor General Waxman, Assistant Attorney Gen-
eral Ogden, Deputy Solicitor General Kneedler, and Lisa
Schiavo Blatt.
Gerald F. Uelmen argued the cause for respondents.
With him on the brief were James J. Brosnahan, Annette
P. Carnegie, Christina Kirk-Kazhe, Robert A. Raich, and
Randy E. Barnett.*
*Janet M. LaRue filed a brief for the Family Research Council as ami-
cus curiae urging reversal.
Briefs of amici curiae urging affirmance were filed for the State of
California by Bill Lockyer, Attorney General, and David De Alba, Special
Assistant Attorney General; for the American Civil Liberties Union et al.
by Steven R. Shapiro, Daniel P. Tokaji, and Jordan C. Budd; for the
American Public Health Association et al. by Daniel N. Abrahamson;
for the Marijuana Policy Project et al. by Cheryl Flax-Davidson; for
the National Organization for the Reform of Marijuana Laws et al. by
R. Keith Stroup, John Wesley Hall, Jr., and Lisa B. Kemler; for Edward
Neil Brundridge et al. by Thomas V. Loran III; and for Sheriff Mark
N. Dion et al. by Julie M. Carpenter.
Briefs of amici curiae were filed for the California Medical Association
et al. by Catherine I. Hanson and Alice P. Mead; and for the Institute on
Global Drug Policy of the Drug Free America Foundation et al. by David
G. Evans and John E. Lamp.

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486 UNITED STATES v. OAKLAND CANNABIS
BUYERS’ COOPERATIVE
Opinion of the Court
Justice Thomas delivered the opinion of the Court.
The Controlled Substances Act, 84 Stat. 1242, 21 U. S. C.
§ 801 et seq., prohibits the manufacture and distribution of
various drugs, including marijuana. In this case, we must
decide whether there is a medical necessity exception to
these prohibitions. We hold that there is not.
I
In November 1996, California voters enacted an initiative
measure entitled the Compassionate Use Act of 1996. At-
tempting “[t]o ensure that seriously ill Californians have the
right to obtain and use marijuana for medical purposes,” Cal.
Health & Safety Code Ann. § 11362.5 (West Supp. 2001), the
statute creates an exception to California laws prohibiting
the possession and cultivation of marijuana. These prohibi-
tions no longer apply to a patient or his primary caregiver
who possesses or cultivates marijuana for the patient’s medi-
cal purposes upon the recommendation or approval of a phy-
sician. Ibid. In the wake of this voter initiative, several
groups organized “medical cannabis dispensaries” to meet
the needs of qualified patients. United States v. Cannabis
Cultivators Club, 5 F. Supp. 2d 1086, 1092 (ND Cal. 1998).
Respondent Oakland Cannabis Buyers’ Cooperative is one of
these groups.
The Cooperative is a not-for-profit organization that oper-
ates in downtown Oakland. A physician serves as medical
director, and registered nurses staff the Cooperative during
business hours. To become a member, a patient must pro-
vide a written statement from a treating physician assenting
to marijuana therapy and must submit to a screening inter-
view. If accepted as a member, the patient receives an iden-
tification card entitling him to obtain marijuana from the
Cooperative.
In January 1998, the United States sued the Cooperative
and its executive director, respondent Jeffrey Jones (to-

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gether, the Cooperative), in the United States District Court
for the Northern District of California. Seeking to enjoin
the Cooperative from distributing and manufacturing mari-
juana,1 the United States argued that, whether or not the
Cooperative’s activities are legal under California law, they
violate federal law. Specifically, the Government argued
that the Cooperative violated the Controlled Substances
Act’s prohibitions on distributing, manufacturing, and pos-
sessing with the intent to distribute or manufacture a con-
trolled substance. 21 U. S. C. § 841(a). Concluding that the
Government had established a probability of success on the
merits, the District Court granted a preliminary injunction.
App. to Pet. for Cert. 39a–40a; 5 F. Supp. 2d, at 1105.
The Cooperative did not appeal the injunction but instead
openly violated it by distributing marijuana to numerous
persons, App. to Pet. for Cert. 21a–23a. To terminate these
violations, the Government initiated contempt proceedings.
In defense, the Cooperative contended that any distributions
were medically necessary. Marijuana is the only drug, ac-
cording to the Cooperative, that can alleviate the severe pain
and other debilitating symptoms of the Cooperative’s pa-
tients. Id., at 29a. The District Court rejected this de-
fense, however, after determining there was insufficient evi-
dence that each recipient of marijuana was in actual danger
of imminent harm without the drug. Id., at 29a–32a. The
District Court found the Cooperative in contempt and, at the
Government’s request, modified the preliminary injunction
to empower the United States Marshal to seize the Coopera-
tive’s premises. Id., at 37a. Although recognizing that
1 The Government requested, and the District Court granted, an injunc-
tion that prohibited the possession of marijuana with the intent to man-
ufacture and distribute, as well as the distribution and manufacture of
marijuana. For simplicity, in this opinion, we refer to these activities col-
lectively as distributing and manufacturing marijuana. The legal issues
are the same for all of these activities.

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“human suffering” could result, the District Court reasoned
that a court’s “equitable powers [do] not permit it to ignore
federal law.” Ibid. Three days later, the District Court
summarily rejected a motion by the Cooperative to modify
the injunction to permit distributions that are medically
necessary.
The Cooperative appealed both the contempt order and
the denial of the Cooperative’s motion to modify. Before the
Court of Appeals for the Ninth Circuit decided the case, how-
ever, the Cooperative voluntarily purged its contempt by
promising the District Court that it would comply with the
initial preliminary injunction. Consequently, the Court of
Appeals determined that the appeal of the contempt order
was moot. 190 F. 3d 1109, 1112–1113 (1999).
The denial of the Cooperative’s motion to modify the in-
junction, however, presented a live controversy that was ap-
pealable under 28 U. S. C. § 1292(a)(1). Reaching the merits
of this issue, the Court of Appeals reversed and remanded.
According to the Court of Appeals, the medical necessity de-
fense was a “legally cognizable defense” that likely would
apply in the circumstances. 190 F. 3d, at 1114. Moreover,
the Court of Appeals reasoned, the District Court errone-
ously “believed that it had no discretion to issue an injunc-
tion that was more limited in scope than the Controlled
Substances Act itself.” Id., at 1114–1115. Because, accord-
ing to the Court of Appeals, district courts retain “broad
equitable discretion” to fashion injunctive relief, the District
Court could have, and should have, weighed the “public in-
terest” and considered factors such as the serious harm
in depriving patients of marijuana. Ibid. Remanding the
case, the Court of Appeals instructed the District Court to
consider “the criteria for a medical necessity exemption, and,
should it modify the injunction, to set forth those criteria
in the modification order.” Id., at 1115. Following these
instructions, the District Court granted the Cooperative’s

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motion to modify the injunction to incorporate a medical
necessity defense.2
The United States petitioned for certiorari to review the
Court of Appeals’ decision that medical necessity is a legally
cognizable defense to violations of the Controlled Substances
Act. Because the decision raises significant questions as to
the ability of the United States to enforce the Nation’s drug
laws, we granted certiorari. 531 U. S. 1010 (2000).
II
The Controlled Substances Act provides that, “[e]xcept as
authorized by this subchapter, it shall be unlawful for any
person knowingly or intentionally . . . to manufacture, dis-
tribute, or dispense, or possess with intent to manufacture,
distribute, or dispense, a controlled substance.” 21 U. S. C.
§ 841(a)(1). The subchapter, in turn, establishes exceptions.
2 The amended preliminary injunction reaffirmed that the Cooperative
is generally enjoined from manufacturing, distributing, and possessing
with the intent to manufacture or distribute marijuana, but it carved out
an exception for cases of medical necessity. Specifically, the District
Court ordered that “[t]he foregoing injunction does not apply to the distri-
bution of cannabis by [the Cooperative] to patient-members who (1) suffer
from a serious medical condition, (2) will suffer imminent harm if the
patient-member does not have access to cannabis, (3) need cannabis for
the treatment of the patient-member’s medical condition, or need cannabis
to alleviate the medical condition or symptoms associated with the medical
condition, and (4) have no reasonable legal alternative to cannabis for the
effective treatment or alleviation of the patient-member’s medical condi-
tion or symptoms associated with the medical condition because the
patient-member has tried all other legal alternatives to cannabis and the
alternatives have been ineffective in treating or alleviating the patient-
member’s medical condition or symptoms associated with the medical con-
dition, or the alternatives result in side effects which the patient-member
cannot reasonably tolerate.” App. to Pet. for Cert. 16a–17a.
The United States appealed the District Court’s order amending the
preliminary injunction. At the Government’s request, we stayed the
order pending the appeal. 530 U. S. 1298 (2000). The Court of Appeals
has postponed oral argument pending our decision in this case.

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Opinion of the Court
For marijuana (and other drugs that have been classified as
“schedule I” controlled substances), there is but one express
exception, and it is available only for Government-approved
research projects, § 823(f). Not conducting such a project,
the Cooperative cannot, and indeed does not, claim this stat-
utory exemption.
The Cooperative contends, however, that notwithstanding
the apparently absolute language of § 841(a), the statute is
subject to additional, implied exceptions, one of which is
medical necessity. According to the Cooperative, because
necessity was a defense at common law, medical necessity
should be read into the Controlled Substances Act. We
disagree.
As an initial matter, we note that it is an open question
whether federal courts ever have authority to recognize a
necessity defense not provided by statute. A necessity de-
fense “traditionally covered the situation where physical
forces beyond the actor’s control rendered illegal conduct the
lesser of two evils.” United States v. Bailey, 444 U. S. 394,
410 (1980). Even at common law, the defense of necessity
was somewhat controversial. See, e. g., Queen v. Dudley &
Stephens, 14 Q. B. 273 (1884). And under our constitutional
system, in which federal crimes are defined by statute rather
than by common law, see United States v. Hudson, 7 Cranch
32, 34 (1812), it is especially so. As we have stated:
“Whether, as a policy matter, an exemption should be
created is a question for legislative judgment, not judicial
inference.” United States v. Rutherford, 442 U. S. 544,
559 (1979). Nonetheless, we recognize that this Court has
discussed the possibility of a necessity defense without
altogether rejecting it. See, e. g., Bailey, supra, at 415. 3
3 The Cooperative is incorrect to suggest that Bailey has settled the
question whether federal courts have authority to recognize a necessity
defense not provided by statute. There, the Court rejected the necessity
defense of a prisoner who contended that adverse prison conditions justi-
fied his prison escape. The Court held that the necessity defense is un-

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We need not decide, however, whether necessity can ever
be a defense when the federal statute does not expressly
provide for it. In this case, to resolve the question pre-
sented, we need only recognize that a medical necessity ex-
ception for marijuana is at odds with the terms of the Con-
trolled Substances Act. The statute, to be sure, does not
explicitly abrogate the defense.4 But its provisions leave no
doubt that the defense is unavailable.
Under any conception of legal necessity, one principle is
clear: The defense cannot succeed when the legislature itself
has made a “determination of values.” 1 W. LaFave & A.
Scott, Substantive Criminal Law § 5.4, p. 629 (1986). In the
case of the Controlled Substances Act, the statute reflects a
determination that marijuana has no medical benefits worthy
of an exception (outside the confines of a Government-
approved research project). Whereas some other drugs can
be dispensed and prescribed for medical use, see 21 U. S. C.
§ 829, the same is not true for marijuana. Indeed, for pur-
poses of the Controlled Substances Act, marijuana has “no
currently accepted medical use” at all. § 812.
The structure of the Act supports this conclusion. The
statute divides drugs into five schedules, depending in part
on whether the particular drug has a currently accepted
available to prisoners, like Bailey, who fail to present evidence of a bona
fide effort to surrender as soon as the claimed necessity had lost its coer-
cive force. 444 U. S., at 415. It was not argued, and so there was no
occasion to consider, whether the statute might be unable to bear any
necessity defense at all. And although the Court noted that Congress
“legislates against a background of Anglo-Saxon common law” and thus
“may” have contemplated a necessity defense, the Court refused to “bal-
anc[e] [the] harms,” explaining that “we are construing an Act of Congress,
not drafting it.” Id., at 415–416, n. 11.
4 We reject the Cooperative’s intimation that elimination of the defense
requires an “explici[t]” statement. Brief for Respondents 21. Consider-
ing that we have never held necessity to be a viable justification for violat-
ing a federal statute, see supra, at 490, and n. 3, and that such a defense
would entail a social balancing that is better left to Congress, we decline
to set the bar so high.

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medical use. The Act then imposes restrictions on the man-
ufacture and distribution of the substance according to the
schedule in which it has been placed. Schedule I is the most
restrictive schedule.5 The Attorney General can include a
drug in schedule I only if the drug “has no currently ac-
cepted medical use in treatment in the United States,” “has
a high potential for abuse,” and has “a lack of accepted safety
for use . . . under medical supervision.” §§ 812(b)(1)(A)–(C).
Under the statute, the Attorney General could not put mari-
juana into schedule I if marijuana had any accepted medical
use.
The Cooperative points out, however, that the Attorney
General did not place marijuana into schedule I. Congress
put it there, and Congress was not required to find that a
drug lacks an accepted medical use before including the drug
in schedule I. We are not persuaded that this distinction
has any significance to our inquiry. Under the Cooperative’s
logic, drugs that Congress places in schedule I could be dis-
tributed when medically necessary whereas drugs that the
Attorney General places in schedule I could not. Nothing
in the statute, however, suggests that there are two tiers
of schedule I narcotics, with drugs in one tier more readily
available than drugs in the other. On the contrary, the stat-
ute consistently treats all schedule I drugs alike. See, e. g.,
§ 823(a) (providing criteria for Attorney General to consider
when determining whether to register an applicant to manu-
facture schedule I controlled substances), § 823(b) (providing
criteria for Attorney General to consider when determining
whether to register an applicant to distribute schedule I con-
trolled substances), § 823(f) (providing procedures for becom-
ing a government-approved research project), § 826 (estab-
lishing production quotas for schedule I drugs). Moreover,
5 As noted, supra, at 490, the only express exception for schedule I drugs
is the Government-approved research project, see 21 U. S. C. § 823(f).
Unlike drugs in other schedules, see § 829, schedule I drugs cannot be
dispensed under a prescription.

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the Cooperative offers no convincing explanation for why
drugs that Congress placed on schedule I should be subject
to fewer controls than the drugs that the Attorney General
placed on the schedule. Indeed, the Cooperative argues
that, in placing marijuana and other drugs on schedule I,
Congress “wishe[d] to assert the most restrictive level of
controls created by the [Controlled Substances Act].” Brief
for Respondents 24. If marijuana should be subject to the
most restrictive level of controls, it should not be treated any
less restrictively than other schedule I drugs.
The Cooperative further argues that use of schedule I
drugs generally—whether placed in schedule I by Congress
or the Attorney General—can be medically necessary, not-
withstanding that they have “no currently accepted medical
use.” According to the Cooperative, a drug may not yet
have achieved general acceptance as a medical treatment but
may nonetheless have medical benefits to a particular patient
or class of patients. We decline to parse the statute in this
manner. It is clear from the text of the Act that Congress
has made a determination that marijuana has no medical
benefits worthy of an exception. The statute expressly con-
templates that many drugs “have a useful and legitimate
medical purpose and are necessary to maintain the health
and general welfare of the American people,” § 801(1), but it
includes no exception at all for any medical use of marijuana.
Unwilling to view this omission as an accident, and unable
in any event to override a legislative determination manifest
in a statute, we reject the Cooperative’s argument.6
6 The Government argues that the 1998 “sense of the Congress” resolu-
tion, 112 Stat. 2681–760 to 2681–761, supports its position that Congress
has foreclosed the medical necessity defense. Entitled “Not Legalizing
Marijuana for Medicinal Use,” the resolution declares that “Congress con-
tinues to support the existing Federal legal process for determining the
safety and efficacy of drugs and opposes efforts to circumvent this process
by legalizing marijuana, and other Schedule I drugs, for medicinal use
without valid scientific evidence and the approval of the Food and Drug
Administration.” Because we conclude that the Controlled Substances

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Finally, the Cooperative contends that we should construe
the Controlled Substances Act to include a medical necessity
defense in order to avoid what it considers to be difficult
constitutional questions. In particular, the Cooperative as-
serts that, shorn of a medical necessity defense, the statute
exceeds Congress’ Commerce Clause powers, violates the
substantive due process rights of patients, and offends the
fundamental liberties of the people under the Fifth, Ninth,
and Tenth Amendments. As the Cooperative acknowledges,
however, the canon of constitutional avoidance has no appli-
cation in the absence of statutory ambiguity. Because we
have no doubt that the Controlled Substances Act cannot
bear a medical necessity defense to distributions of mari-
juana, we do not find guidance in this avoidance principle.
Nor do we consider the underlying constitutional issues
today. Because the Court of Appeals did not address these
claims, we decline to do so in the first instance.
For these reasons, we hold that medical necessity is not a
defense to manufacturing and distributing marijuana.7 The
Act cannot sustain the medical necessity defense, we need not consider
whether the 1998 “sense of the Congress resolution” is additional evidence
of a legislative determination to eliminate the defense.
7 Lest there be any confusion, we clarify that nothing in our analysis,
or the statute, suggests that a distinction should be drawn between the
prohibitions on manufacturing and distributing and the other prohibitions
in the Controlled Substances Act. Furthermore, the very point of our
holding is that there is no medical necessity exception to the prohibitions
at issue, even when the patient is “seriously ill” and lacks alternative ave-
nues for relief. Indeed, it is the Cooperative’s argument that its patients
are “seriously ill,” see, e. g., Brief for Respondents 11, 13, 17, and lacking
“alternatives,” see, e. g., id., at 13. We reject the argument that these
factors warrant a medical necessity exception. If we did not, we would
be affirming instead of reversing the Court of Appeals.
Finally, we share Justice Stevens’ concern for “showing respect for
the sovereign States that comprise our Federal Union.” Post, at 502
(opinion concurring in judgment). However, we are “construing an Act
of Congress, not drafting it.” United States v. Bailey, 444 U. S. 394, 415,
n. 11 (1980). Because federal courts interpret, rather than author, the

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Court of Appeals erred when it held that medical necessity
is a “legally cognizable defense.” 190 F. 3d, at 1114. It fur-
ther erred when it instructed the District Court on remand
to consider “the criteria for a medical necessity exemption,
and, should it modify the injunction, to set forth those crite-
ria in the modification order.” Id., at 1115.
III
The Cooperative contends that, even if the Controlled Sub-
stances Act forecloses the medical necessity defense, there
is an alternative ground for affirming the Court of Appeals.
This case, the Cooperative reminds us, arises from a motion
to modify an injunction to permit distributions that are medi-
cally necessary. According to the Cooperative, the Court of
Appeals was correct that the District Court had “broad equi-
table discretion” to tailor the injunctive relief to account for
medical necessity, irrespective of whether there is a legal
defense of necessity in the statute. Id., at 1114. To sustain
the judgment below, the argument goes, we need only reaf-
firm that federal courts, in the exercise of their equity juris-
diction, have discretion to modify an injunction based upon
a weighing of the public interest.8
We disagree. Although district courts whose equity pow-
ers have been properly invoked indeed have discretion in
fashioning injunctive relief (in the absence of a statutory re-
striction), the Court of Appeals erred concerning the factors
that the district courts may consider in exercising such
discretion.
federal criminal code, we are not at liberty to rewrite it. Nor are we
passing today on a constitutional question, such as whether the Controlled
Substances Act exceeds Congress’ power under the Commerce Clause.
8 Notwithstanding Justice Stevens’ concerns, post, at 502–503, it is
appropriate for us to address this issue because this case arises from a
motion to modify the injunction, because the Court of Appeals held that
the District Court misconstrued its equitable discretion, and because the
Cooperative offers this conclusion as an alternative ground for affirmance.

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Opinion of the Court
A
As an initial matter, the Cooperative is correct that, when
district courts are properly acting as courts of equity, they
have discretion unless a statute clearly provides otherwise.
For “several hundred years,” courts of equity have enjoyed
“sound discretion” to consider the “necessities of the public
interest” when fashioning injunctive relief. Hecht Co. v.
Bowles, 321 U. S. 321, 329–330 (1944). See also id., at 329
(“The essence of equity jurisdiction has been the power of
the Chancellor to do equity and to mould each decree to the
necessities of the particular case. Flexibility rather than ri-
gidity has distinguished it”); Weinberger v. Romero-Barcelo,
456 U. S. 305, 312 (1982) (“In exercising their sound discre-
tion, courts of equity should pay particular regard for the
public consequences in employing the extraordinary remedy
of injunction”). Such discretion is displaced only by a “clear
and valid legislative command.” Porter v. Warner Holding
Co., 328 U. S. 395, 398 (1946). See also Romero-Barcelo,
supra, at 313 (“Of course, Congress may intervene and guide
or control the exercise of the courts’ discretion, but we do not
lightly assume that Congress has intended to depart from
established principles”).
The Cooperative is also correct that the District Court in
this case had discretion. The Controlled Substances Act
vests district courts with jurisdiction to enjoin violations of
the Act, 21 U. S. C. § 882(a). But a “grant of jurisdiction to
issue [equitable relief] hardly suggests an absolute duty to
do so under any and all circumstances,” Hecht, supra, at 329
(emphasis deleted). Because the District Court’s use of eq-
uitable power is not textually required by any “clear and
valid legislative command,” the court did not have to issue
an injunction.
TVA v. Hill, 437 U. S. 153 (1978), does not support the
Government’s contention that the District Court lacked dis-
cretion in fashioning injunctive relief. In Hill, the Court
held that the Endangered Species Act of 1973 required the

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Opinion of the Court
District Court to enjoin completion of a dam, whose opera-
tion would either eradicate the known population of the snail
darter or destroy its critical habitat. Id., at 193–195. The
District Court lacked discretion because an injunction was
the “only means of ensuring compliance.” Romero-Barcelo,
supra, at 314 (explaining why the District Court in Hill
lacked discretion). Congress’ “order of priorities,” as ex-
pressed in the statute, would be deprived of effect if the
District Court could choose to deny injunctive relief. Hill,
supra, at 194. In effect, the District Court had only a Hob-
son’s choice. By contrast, with respect to the Controlled
Substances Act, criminal enforcement is an alternative, and
indeed the customary, means of ensuring compliance with the
statute. Congress’ resolution of the policy issues can be
(and usually is) upheld without an injunction.
B
But the mere fact that the District Court had discretion
does not suggest that the District Court, when evaluating
the motion to modify the injunction, could consider any and
all factors that might relate to the public interest or the con-
veniences of the parties, including the medical needs of the
Cooperative’s patients. On the contrary, a court sitting in
equity cannot “ignore the judgment of Congress, deliber-
ately expressed in legislation.” Virginian R. Co. v. Railway
Employees, 300 U. S. 515, 551 (1937). A district court can-
not, for example, override Congress’ policy choice, articu-
lated in a statute, as to what behavior should be prohibited.
“Once Congress, exercising its delegated powers, has decided
the order of priorities in a given area, it is . . . for the courts
to enforce them when enforcement is sought.” Hill, 437
U. S., at 194. Courts of equity cannot, in their discretion,
reject the balance that Congress has struck in a statute.
Id., at 194–195. Their choice (unless there is statutory lan-
guage to the contrary) is simply whether a particular means
of enforcing the statute should be chosen over another per-

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Opinion of the Court
missible means; their choice is not whether enforcement is
preferable to no enforcement at all.9 Consequently, when a
court of equity exercises its discretion, it may not consider
the advantages and disadvantages of nonenforcement of the
statute, but only the advantages and disadvantages of “em-
ploying the extraordinary remedy of injunction,” Romero-
Barcelo, 456 U. S., at 312, over the other available methods
of enforcement. Cf. id., at 316 (referring to “discretion to
rely on remedies other than an immediate prohibitory injunc-
tion”). To the extent the district court considers the public
interest and the conveniences of the parties, the court is lim-
ited to evaluating how such interest and conveniences are
affected by the selection of an injunction over other enforce-
ment mechanisms.
C
In this case, the Court of Appeals erred by considering
relevant the evidence that some people have “serious medical
conditions for whom the use of cannabis is necessary in order
to treat or alleviate those conditions or their symptoms,”
that these people “will suffer serious harm if they are denied
cannabis,” and that “there is no legal alternative to cannabis
9 Hecht Co. v. Bowles, 321 U. S. 321 (1944), for example, held that the
District Court was not required to issue an injunction to restrain viola-
tions of the Emergency Price Control Act of 1942 and regulations there-
under when “some ‘other order’ might be more appropriate, or at least so
appear to the court.” Id., at 328 (quoting statutory provision that enabled
district court to issue an injunction, a restraining order, “or other order”).
Weinberger v. Romero-Barcelo, 456 U. S. 305 (1982), held that a District
Court had discretion not to issue an injunction precluding the United
States Navy from releasing ordnance into water, but to rely on other
means of ensuring compliance, including ordering the Navy to obtain a
permit. Id., at 314–318. See also Amoco Production Co. v. Gambell, 480
U. S. 531, 544–546 (1987) (holding that a District Court did not err in de-
clining to issue an injunction to bar exploratory drilling on Alaskan public
lands, because the District Court’s decision “did not undermine” the policy
of the Alaska National Interest Lands Conservation Act, 16 U. S. C. § 3120,
and because the Secretary of the Interior had other means of meaningfully
complying with the statute).

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Stevens, J., concurring in judgment
for the effective treatment of their medical conditions.” 190
F. 3d, at 1115. As explained above, in the Controlled Sub-
stances Act, the balance already has been struck against a
medical necessity exception. Because the statutory prohibi-
tions cover even those who have what could be termed a
medical necessity, the Act precludes consideration of this evi-
dence. It was thus error for the Court of Appeals to in-
struct the District Court on remand to consider “the criteria
for a medical necessity exemption, and, should it modify the
injunction, to set forth those criteria in the modification
order.” Ibid.
* * *
The judgment of the Court of Appeals is reversed, and
the case is remanded for further proceedings consistent with
this opinion.
It is so ordered.
Justice Breyer took no part in the consideration or
decision of this case.
Justice Stevens, with whom Justice Souter and
Justice Ginsburg join, concurring in the judgment.
Lest the Court’s narrow holding be lost in its broad dicta,
let me restate it here: “[W]e hold that medical necessity is
not a defense to manufacturing and distributing mari-
juana.” Ante, at 494 (emphasis added). This confined hold-
ing is consistent with our grant of certiorari, which was lim-
ited to the question “[w]hether the Controlled Substances
Act, 21 U. S. C. 801 et seq., forecloses a medical necessity de-
fense to the Act’s prohibition against manufacturing and
distributing marijuana, a Schedule I controlled substance.”
Pet. for Cert. (I) (emphasis added). And, at least with re-
spect to distribution, this holding is consistent with how the
issue was raised and litigated below. As stated by the Dis-
trict Court, the question before it was “whether [respond-
ents’] admitted distribution of marijuana for use by seri-

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ously ill persons upon a physician’s recommendation violates
federal law,” and if so, whether such distribution “should be
enjoined pursuant to the injunctive relief provisions of the
federal Controlled Substances Act.” United States v. Can-
nabis Cultivators Club, 5 F. Supp. 2d 1086, 1091 (ND Cal.
1998) (emphasis added).
Accordingly, in the lower courts as well as here, respond-
ents have raised the medical necessity defense as a justifica-
tion for distributing marijuana to cooperative members, and
it was in that context that the Ninth Circuit determined that
respondents had “a legally cognizable defense.” 190 F. 3d
1109, 1114 (1999). The Court is surely correct to reverse
that determination. Congress’ classification of marijuana as
a schedule I controlled substance—that is, one that cannot
be distributed outside of approved research projects, see 21
U. S. C. §§ 812, 823(f), 829—makes it clear that “the Con-
trolled Substances Act cannot bear a medical necessity de-
fense to distributions of marijuana,” ante, at 494 (emphasis
added).1
Apart from its limited holding, the Court takes two unwar-
ranted and unfortunate excursions that prevent me from
joining its opinion. First, the Court reaches beyond its
holding, and beyond the facts of the case, by suggesting that
the defense of necessity is unavailable for anyone under the
1 In any event, respondents do not fit the paradigm of a defendant who
may assert necessity. The defense “traditionally covered the situation
where physical forces beyond the actor’s control rendered illegal conduct
the lesser of two evils.” United States v. Bailey, 444 U. S. 394, 410 (1980);
see generally 1 W. LaFave & A. Scott, Substantive Criminal Law § 5.4,
pp. 627–640 (1986). Respondents, on the other hand, have not been forced
to confront a choice of evils—violating federal law by distributing mari-
juana to seriously ill patients or letting those individuals suffer—but have
thrust that choice upon themselves by electing to become distributors for
such patients. Of course, respondents also cannot claim necessity based
upon the choice of evils facing seriously ill patients, as that is not the same
choice respondents face.

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Stevens, J., concurring in judgment
Controlled Substances Act. Ante, at 491–493, 494–495, n. 7,
499. Because necessity was raised in this case as a defense
to distribution, the Court need not venture an opinion on
whether the defense is available to anyone other than dis-
tributors. Most notably, whether the defense might be
available to a seriously ill patient for whom there is no alter-
native means of avoiding starvation or extraordinary suffer-
ing is a difficult issue that is not presented here.2
Second, the Court gratuitously casts doubt on “whether
necessity can ever be a defense” to any federal statute that
does not explicitly provide for it, calling such a defense into
question by a misleading reference to its existence as an
“open question.” Ante, at 490, 491. By contrast, our prece-
dent has expressed no doubt about the viability of the
common-law defense, even in the context of federal criminal
statutes that do not provide for it in so many words. See,
e. g., United States v. Bailey, 444 U. S. 394, 415 (1980) (“We
therefore hold that, where a criminal defendant is charged
with escape and claims that he is entitled to an instruction
on the theory of duress or necessity, he must proffer evidence
of a bona fide effort to surrender or return to custody as soon
as the claimed duress or necessity had lost its coercive
force”); id., at 416, n. 11 (“Our principal difference with the
dissent, therefore, is not as to the existence of such a defense
but as to the importance of surrender as an element of it”
(emphasis added)). Indeed, the Court’s comment on the
general availability of the necessity defense is completely un-
necessary because the Government has made no such sug-
gestion. Cf. Brief for United States 17–18 (narrowly ar-
guing that necessity defense cannot succeed if legislature has
2 As a result, perhaps the most glaring example of the Court’s dicta is
its footnote 7, where it opines that “nothing in our analysis, or the statute,
suggests that a distinction should be drawn between the prohibitions on
manufacturing and distributing and the other prohibitions in the Con-
trolled Substances Act.” Ante, at 494, n. 7.

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already “canvassed the issue” and precluded it for a particu-
lar statute (internal quotation marks omitted)). The Court’s
opinion on this point is pure dictum.
The overbroad language of the Court’s opinion is especially
unfortunate given the importance of showing respect for the
sovereign States that comprise our Federal Union. That re-
spect imposes a duty on federal courts, whenever possible,
to avoid or minimize conflict between federal and state law,
particularly in situations in which the citizens of a State have
chosen to “serve as a laboratory” in the trial of “novel social
and economic experiments without risk to the rest of the
country.” New State Ice Co. v. Liebmann, 285 U. S. 262, 311
(1932) (Brandeis, J., dissenting). In my view, this is such a
case.3 By passing Proposition 215, California voters have
decided that seriously ill patients and their primary caregiv-
ers should be exempt from prosecution under state laws for
cultivating and possessing marijuana if the patient’s physi-
cian recommends using the drug for treatment.4 This case
does not call upon the Court to deprive all such patients of
the benefit of the necessity defense to federal prosecution,
when the case itself does not involve any such patients.
An additional point deserves emphasis. This case does
not require us to rule on the scope of the District Court’s
discretion to enjoin, or to refuse to enjoin, the possession
of marijuana or other potential violations of the Controlled
3 Cf. Feeney, Bush Backs States’ Rights on Marijuana: He Opposes Medi-
cal Use But Favors Local Control, Dallas Morning News, Oct. 20, 1999,
p. 6A, 1999 WL 28018944 (then-Governor Bush supporting state self-
determination on medical marijuana use).
4 Since 1996, six other States—Alaska, Colorado, Maine, Nevada, Ore-
gon, and Washington—have passed medical marijuana initiatives, and
Hawaii has enacted a similar measure through its legislature. See Alaska
Stat. Ann. §§ 11.71.090, 17.37.010 to 17.37.080 (2000); Colo. Const., Art.
XVIII, § 14; Haw. Rev. Stat. §§ 329–121 to 329–128 (Supp. 2000); Me. Rev.
Stat. Ann., Tit. 22, § 2383–B(5) (Supp. 2000); Nev. Const., Art. 4, § 38; Ore.
Rev. Stat. §§ 475.300 to 475.346 (1999); Wash. Rev. Code §§ 69.51A.005 to
69.51A.902 (1997 and Supp. 2000–2001).

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Substances Act by a seriously ill patient for whom the drug
may be a necessity. Whether it would be an abuse of discre-
tion for the District Court to refuse to enjoin those sorts of
violations, and whether the District Court may consider the
availability of the necessity defense for that sort of violator,
are questions that should be decided on the authority of
cases such as Hecht Co. v. Bowles, 321 U. S. 321 (1944), and
Weinberger v. Romero-Barcelo, 456 U. S. 305 (1982), and that
properly should be left “open” by this case.
I join the Court’s judgment of reversal because I agree
that a distributor of marijuana does not have a medical ne-
cessity defense under the Controlled Substances Act. I do
not, however, join the dicta in the Court’s opinion.