[1224]*1224OPINION
PREGERSON, Circuit Judge:
Two of the appellants, Angel MeClary Raich and Diane Monson, are seriously ill Californians who use marijuana for medical purposes on the recommendation of their doctors. Such use is legal under California’s Compassionate Use Act. Mon-son grows her own medical marijuana. The remaining two appellants, John Doe Number One and John Doe Number Two, assist Raich in growing her marijuana. On October 9, 2002, the appellants filed suit against John Ashcroft, the Attorney General of the United States, and Asa Hutchinson, the Administrator of the Drug Enforcement Administration, seeking injunctive and declaratory relief based on the alleged uneonstitutionality of the federal Controlled Substances Act. The appellants also seek a declaration that the medical necessity defense precludes enforcement of that act against them.
On March 5, 2003, the district court denied the appellants’ motion for a preliminary injunction because the appellants had not established a sufficient likelihood of success on the merits. That ruling is now before us.
FACTUAL AND PROCEDURAL HISTORY
A. Statutory Scheme
1. The Controlled Substances Act
Congress enacted the Controlled Substances Act, 21 U.S.C. § 801 et seq., (“CSA”) as part of the Comprehensive Drug Abuse Prevention and Control Act of 1970, Pub.L. 91-513, 84 Stat. 1236. The CSA establishes five “schedules” of certain drugs and other substances and designates these items “controlled substances.” 21 U.S.C. §§ 802(6), 812(a). Marijuana is a schedule I controlled substance. Id. § 812(c). For a drug or other substance to be designated a schedule I controlled substance, it must be found (1) that the substance “has a high potential for abuse”; (2) that the substance “has no currently accepted medical use in treatment in the United States”; and (3) that there is “a lack of accepted safety for use of the drug or other substance under medical supervision.” Id. at § 812(b)(1). The CSA sets forth procedures by which the schedules may be modified. Id. at § 811(a).
Among other things, the CSA makes it unlawful to knowingly or intentionally “manufacture, distribute, or dispense, or possess with intent to manufacture, distribute, or dispense, a controlled substance,” except as provided for in the statute. 21 U.S.C. § 841(a)(1). Possession of a controlled substance, except as authorized under the CSA, is also unlawful. Id. § 844(a).
Congress set forth certain findings and declarations in the CSA, the most relevant of which are as follows:
(2) The illegal importation, manufacture, distribution, and possession and improper use of controlled substances have a substantial and detrimental effect on the health and general welfare of the American people.
(4) Local distribution and possession of controlled substances contribute to swelling the interstate traffic in such substances.
(5) Controlled substances manufactured and distributed intrastate cannot be differentiated from controlled substances manufactured and distributed interstate. Thus, is it not feasible to distinguish, in terms of controls, between controlled substances manufactured and distributed interstate and controlled substances manufactured and distributed intrastate.
(6) Federal control of the intrastate incidents of the traffic in controlled sub[1225]*1225stances is essential to the effective control of the interstate incidents of such traffic.
21 U.S.C. § 801.
2. California’s Compassionate Use Act of 1996
In 1996, California voters passed Proposition 215, which is codified as the Compassionate Use Act of 1996 (“Compassionate Use Act”), Cal. Health & Safety Code § 11362.5. Among other purposes, the Compassionate Use Act is intended
[t]o ensure that seriously ill Californians have the right to obtain and use marijuana for medical purposes where that medical use is deemed appropriate and has been recommended by a physician who has determined that the person’s health would benefit from the use of marijuana in the treatment of cancer, anorexia, AIDS, chronic pain, spasticity, glaucoma, arthritis, migraine, or any other illness for which marijuana provides relief.
Id. § 11362.5(b)(1)(A). The Compassionate Use Act is also intended “[t]o ensure that patients and their primary caregivers who obtain and use marijuana for medical purposes upon the recommendation of a physician are not subject to criminal prosecution or sanction.” Id. § 11362.5(b)(1)(B). To these ends, the Compassionate Use Act exempts “a patient, or [] a patient’s primary caregiver, who possesses or cultivates marijuana for the personal medical purposes of the patient upon the written or oral recommendation or approval of a physician” from certain other California code sections that make possession or cultivation of marijuana illegal. Id. § 11362.5(d).
B. Factual Background
Appellants Angel McClary Raich and Diane Monson (the “patient-appellants”) axe California citizens who currently use marijuana as a medical treatment. Appellant Raich has been diagnosed with more than ten serious medical conditions, including an inoperable brain tumor, life-threatening weight loss, a seizure disorder, nausea, and several chronic pain disorders. Appellant Monson suffers from severe chronic back pain and constant, painful muscle spasms. Her doctor states that these symptoms are caused by a degenerative disease of the spine.
Raich has been using marijuana as a medication for over five years, every two waking hours of every day. Her doctor contends that Raich has tried essentially all other legal alternatives and all are either ineffective or result in intolerable side effects; her doctor has provided a list of thirty-five medications that fall into the latter category alone. Raich’s doctor states that foregoing marijuana treatment may be fatal. Monson has been using marijuana as a medication since 1999. Monson’s doctor also contends that alternative medications have been tried and are either ineffective or produce intolerable side effects. As the district court put it: “Traditional medicine has utterly failed these women.... ”
Appellant Monson cultivates her own marijuana. Raich is unable to cultivate her own. Instead, her two caregivers, appellants John Doe Number One and John Doe Number Two, grow it for her. These caregivers provide Raich with her marijuana free of charge. They have sued anonymously in order to protect Raich’s supply of medical marijuana. In growing marijuana for Raich, they allegedly use only soil, water, .nutrients, growing equipment, supplies and lumber -originating from or manufactured within California. Although these caregivers cultivate marijuana for Raich, she processes some of the marijuana into cannabis oils, balm, and foods.
On August 15, 2002, deputies from the Butte County Sheriffs Department and agents from the Drug Enforcement Agen[1226]*1226cy (“DEA”) came to Monson’s home. The sheriffs deputies concluded that Monson’s use of marijuana was legal under the Compassionate Use Act. However, after a three-hour standoff involving the Butte County District Attorney and the United States Attorney for the Eastern District of California, the DEA agents seized and destroyed Monson’s six cannabis plants.
C. Procedural History
Fearing raids in the future and the prospect of being deprived of medicinal marijuana, the appellants sued the United States Attorney General John Ashcroft and the Administrator of the DEA Asa Hutchison on October 9, 2002. Their suit seeks declaratory relief and preliminary and permanent injunctive relief. They seek a declaration that the CSA is unconstitutional to the extent it purports to prevent them from possessing, obtaining, manufacturing, or providing cannabis for medical use. The appellants also seek a declaration that the doctrine of medical necessity precludes enforcement of the CSA to prevent Raich and Monson from possessing, obtaining, or manufacturing cannabis for their personal medical use.
On March 5, 2003, the district court denied the appellants’ motion for a preliminary injunction. The district court found that, “despite the gravity of plaintiffs’ need for medical cannabis, and despite the concrete interest of California to provide it for individuals like them,” the appellants had not established the required “ ‘irreducible minimum’ of a likelihood of success on the merits under the law of this Circuit....” The appellants filed a timely notice of appeal on March 12, 2003. We have jurisdiction to hear this interlocutory appeal pursuant to 28 U.S.C. § 1292(a)(1).1
STANDARD OF REVIEW
A district court’s order regarding preliminary injunctive relief is subject to limited review. United States v. Peninsula Communications, Inc., 287 F.3d 832, 839 (9th Cir.2002). The grant or denial of a preliminary injunction will be reversed only where the district court abused its discretion or based its decision on an erroneous legal standard or on clearly erroneous findings of fact. Id. The legal premises underlying a preliminary injunction are reviewed de novo. See A & M Records, Inc. v. Napster, Inc., 284 F.3d 1091, 1096 (9th Cir.2002); Foti v. City of Menlo Park, 146 F.3d 629, 634-35 (9th Cir.1998) (“Although we review a district court’s decision to deny a motion for a preliminary injunction for an abuse of discretion, we review the legal issues underlying the district [1227]*1227court’s decision de novo.” (citations omitted)).
ANALYSIS
The traditional test for granting preliminary injunctive relief requires the applicant to demonstrate: (1) a likelihood of success on the merits; (2) a significant threat of irreparable injury; (3) that the balance of hardships favors the applicant; and (4) whether any public interest favors granting an injunction. See Dollar Rent A Car of Wash., Inc. v. Travelers Indem. Co., 774 F.2d 1371, 1374 (9th Cir.1985); see also Schwarzer, Tashima & Wagstaffe, Cal. Prac. Guide: Fed. Civ. Pro. Before Trial, ¶ 13:44 at 13-15 (The Rutter Group 2003).
Our court also uses an alternative test that requires the applicant to demonstrate either: a combination of probable success on the merits and the possibility of irreparable injury; or serious questions going to the merits and that the balance of hardships tips sharply in the applicant’s favor. See First Brands Corp. v. Fred Meyer, Inc., 809 F.2d 1378, 1381 (9th Cir.1987). These two tests are not inconsistent. Rather, they represent a continuum of equitable discretion, whereby “the greater the relative hardship to the moving party, the less probability of success must be shown.” Nat’l Ctr. for Immigrants Rights, Inc. v. INS, 743 F.2d 1365, 1369 (9th Cir.1984).
A. The Meñts of the Appellants’ Case
Congress passed the CSA based on its authority under the Commerce Clause of the Constitution. The Commerce Clause grants Congress the power to “regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes....” U.S. Const. art. I, § 8, cl. 3. The appellants argue that the Commerce Clause cannot support the exercise of federal authority over the appellants’ activities. The Supreme Court expressly reserved this issue in its recent decision, United States v. Oakland Cannabis Buyers’ Cooperative, 532 U.S. 483, 494 n. 7, 121 S.Ct. 1711, 149 L.Ed.2d 722 (2001) (“Nor are we passing today on a constitutional question, such as whether the Controlled Substances Act exceeds Congress’ power under the Commerce Clause.”). We find that the appellants have demonstrated a strong likelihood of success on their claim that, as applied to them, the CSA is an unconstitutional exercise of Congress’ Commerce Clause authority. We decline to reach the appellants’ other arguments, which are based on the principles of federalism embodied in the Tenth Amendment, the appellants’ alleged fundamental rights under the Fifth and Ninth Amendments, and the doctrine of medical necessity.
1. Defining the Class of Activities
The district court found that the Commerce Clause supports the application of the CSA to the appellants. Indeed, we have upheld the CSA in the face of past Commerce Clause challenges. See United States v. Bramble, 103 F.3d 1475, 1479-80 (9th Cir.1996); United States v. Tisor, 96 F.3d 370, 375 (9th Cir.1996); United States v. Kim, 94 F.3d 1247, 1249-50 (9th Cir.1996); United States v. Visman, 919 F.2d 1390, 1393 (9th Cir.1990); United States v. Montes-Zarate, 552 F.2d 1330, 1331 (9th Cir.1977); United States v. Rodriquez-Camacho, 468 F.2d 1220, 1222 (9th Cir.1972). But none of the cases in which the Ninth Circuit has upheld the CSA on Commerce Clause grounds involved the use, possession, or cultivation of marijuana for medical purposes.
In arguing that these cases should govern here and should foreclose the appellants’ Commerce Clause challenge, the appellees correctly note that “ ‘where a general regulatory statute bears a sub[1228]*1228stantial relation to commerce, the de minimis character of individual instances arising under that statute is of no consequence.’” United States v. Lopez, 514 U.S. 549, 558, 115 S.Ct. 1624, 131 L.Ed.2d 626 (1995) (quoting Maryland v. Wirtz, 392 U.S. 183, 197 n. 27, 88 S.Ct. 2017, 20 L.Ed.2d 1020 (1968) (first emphasis added in Lopez)). In Visman, we upheld the CSA on Commerce Clause grounds and restated this principle: “ “Where the class of activities is regulated and that class is within the reach of federal power, the courts have no power to excise, as trivial, individual instances of the class.’ ” 919 F.2d at 1393 (quoting Perez v. United States, 402 U.S. 146, 154, 91 S.Ct. 1357, 28 L.Ed.2d 686 (1971)) (emphasis by Vis-man; quotation marks omitted).2
But here the appellants are not only claiming that their activities do not have the same effect on interstate commerce as activities in other cases where the CSA has been upheld. Rather, they contend that, whereas the earlier cases concerned drug trafficking, the appellants’ conduct constitutes a separate and distinct class of activities: the intrastate, noncommercial cultivation and possession of cannabis for personal medical purposes as recommended by a patient’s physician pursuant to valid California state law.
Clearly, the way in which the activity or class of activities is defined is critical. We find that the appellants’ class of activities — the intrastate, noncommercial cultivation, possession and use of marijuana for personal medical purposes on the advice of a physician — is, in fact, different in kind from drug trafficking. For instance, concern regarding users’ health and safety is significantly different in the medicinal marijuana context, where the use is pursuant to a physician’s recommendation. Further, the limited medicinal use of marijuana as recommended by a physician arguably does not raise the same policy concerns regarding the spread of drug abuse. Moreover, this limited use is clearly distinct from the broader illicit drug -markets — as well as any broader commercial market for medicinal marijuana — insofar as the medicinal marijuana at issue in this case is not intended for, nor does it enter, the stream of commerce.
A narrow categorization of the appellants’ activity is supported by our recent decision in United States v. McCoy, 323 F.3d 1114 (9th Cir.2003). In McCoy, we held that 18 U.S.C. § 2252(a)(4)(B), a statute purportedly prohibiting the possession of child pornography, was unconstitutional as applied to intrastate possession of a visual depiction (or depictions) that has not been mailed, shipped, or transported interstate and is not intended for interstate distribution, or for any economic or commercial use, including the exchange of the prohibited material for other prohibited material. See McCoy, 323 F.3d at 1115. McCoy involved a photograph taken at home of a mother and daughter with their genital areas exposed. Id. at 1115. The photograph never entered into and was never intended for interstate or foreign commerce. Id. at 1132. The dissent in McCoy argued that the majority had engaged in an impermissible as-applied analysis, that the activity fell within the language of the statute, and that the majority was attempting to excise a particular act as trivial. See id. at 1134, 1140-41 (Trott, J., dissenting). The majority held that the conduct at issue in McCoy represents a “substantial portion” of the conduct covered by the relevant statute and therefore can be considered a separate class of activity. Id. at 1132.
Under McCoy, the class of activities at issue in this case can properly be defined [1229]*1229as the intrastate, noncommercial cultivation, possession and use of marijuana for personal medical purposes on the advice of a physician and in accordance with state law. This class of activities does not involve sale, exchange, or distribution. As was the case in McCoy, the class of activities here represents a substantial portion of the conduct covered by the statute — at the time of the motion for a preliminary injunction, Alaska, Arizona, California, Colorado, Hawaii, Maine, Nevada, Oregon, and Washington had passed laws permitting cultivation and use of marijuana for medical purposes. See McCoy, 323 F.3d at 1132 (“This class of activity represents a substantial portion of the conduct covered by [the statute].”).
2. Substantial Effect on Interstate Commerce
We must now answer the question whether this class of activities has an effect on interstate commerce sufficient to make it subject to federal regulation under the Commerce Clause. See Visman, 919 F.2d at 1392 (“In Perez ... the Court ruled that the defendants’ local, illegal activity of loan sharking was within a ‘class of activity’ that adversely affected interstate commerce and Congress had the power to regulate it.”). In two recent Commerce Clause decisions, the Supreme Court has refined Commerce Clause analysis. In Lopez, 514 U.S. 549, 115 S.Ct. 1624, 131 L.Ed.2d 626 (1995), the Court struck down the Gun-Free School Zones Act of 1990 as an unconstitutional exercise of power under the Commerce Clause. Lopez set forth three categories of activity that Congress may properly regulate under the Commerce Clause: the “use of the channels of interstate commerce”; the “in-strumentalities of interstate commerce, or persons or things in interstate commerce, even though the threat may come only from intrastate activities”; and “those activities having a substantial relation to interstate commerce, ie., those activities that substantially affect interstate commerce.” 514 U.S. at 558-59, 115 S.Ct. 1624 (citations omitted). This case involves the third category of activity.
In United States v. Morrison, 529 U.S. 598, 120 S.Ct. 1740, 146 L.Ed.2d 658 (2000), the Supreme Court clarified Commerce Clause analysis under this third category. In that case, the Court held that the Violence Against Women Act was an invalid exercise of federal power under the Commerce Clause. 529 U.S. at 627, 120 S.Ct. 1740. Morrison established a controlling four-factor test for determining whether a regulated activity “substantially affects” interstate commerce: (1) whether the statute regulates commerce or any sort of economic enterprise; (2) whether the statute contains any “express jurisdictional element that might limit its reach to a discrete set” of cases; (3) whether the statute or its legislative history contains “express congressional findings” regarding the effects of the regulated activity upon interstate commerce; and (4) whether the link between the regulated activity and a substantial effect on interstate commerce is “attenuated.” Morrison, 529 U.S. at 610-12, 120 S.Ct. 1740; see also McCoy, 323 F.3d at 1119. The first and the fourth factors are the most important. McCoy, 323 F.3d at 1119.
a. Whether the Statute Regulates Commerce or Any Sort of Economic Enterprise
As applied to the limited class of activities presented by this case, the CSA does not regulate commerce or any sort of economic enterprise. The cultivation, possession, and use of marijuana for medicinal purposes and not for exchange or distribution is not properly characterized as commercial or economic activity. Lacking sale, exchange or distribution, the activity does not possess the essential elements of [1230]*1230commerce. See Black’s Law Diotionasy (7th ed.1999) (“commerce”: “The exchange of goods and services, esp. on a large scale involving transportation between cities, states, and nations.”).3
On this point, the instant ease is again analogous to McCoy. The McCoy court concluded “that simple intrastate possession is not, by itself, either commercial or economic in nature, that a ‘home-grown’ picture of a child taken and maintained for personal use is not a fungible product, and that there is no economic connection — supply and demand or otherwise — between possession of such a picture and the national multi-million dollar commercial pornography industry.” Id. at 1131.
As the photograph in McCoy stood in contrast to the commercial nature of the larger child pornography industry, so does the medicinal marijuana use at issue in this case stand in contrast to the larger illicit drug trafficking industry. And it is the commercial nature of drug trafficking activities that has formed the basis of prior Ninth Circuit decisions upholding the CSA on Commerce Clause grounds. See, e.g., Tisor, 96 F.3d at 375 (“Intrastate distribution and sale of methamphetamine are commercial activities. The challenged laws are part of a wider regulatory scheme criminalizing interstate and intrastate commerce in drugs.” (emphasis added)); Kim, 94 F.3d at 1250 (“After Lopez, we again acknowledged that drug trafficking affects interstate commerce.” (emphasis added)).
The parties debate whether the “aggregation principle” of Wickard v. Filburn, 317 U.S. 111, 63 S.Ct. 82, 87 L.Ed. 122 (1942), should be employed, presumably to support a finding that the cumulative effect of the activities in this case has a commercial impact. As the regulated activity in this case is not commercial, Wickard’s aggregation analysis is not applicable. Morrison, 529 U.S. at 611 n. 4, 120 S.Ct. 1740 (“[I]n every case where we have sustained federal regulation under the aggregation principle in Wickard ... the regulated activity was of an apparent commercial character.”); McCoy, 323 F.3d at 1120 (“In Lopez, the court approved of Wickard’s rationale only in relation to activity the economic nature of which was obvious.” (citing Lopez, 514 U.S. at 558, 115 S.Ct. 1624)); United States v. Ballinger, 312 F.3d 1264, 1270 (11th Cir.2002) (“No such aggregation of local effects is constitutionally permissible in reviewing congressional regulation of intrastate, non-economic activity.”).4
The majority in McCoy went on to examine whether the possession of child por[1231]*1231nography at issue in that case could fit within the Wiekard analysis, largely because a pre-Morrison Third Circuit decision had done just that. See 323 F.3d at 1121-22. The parties pick up on this discussion and debate whether, unlike the child pornography in McCoy, the marijuana at issue here is “fungible” such that the aggregation principle should apply. This debate is unnecessary in light of Supreme Court precedent suggesting that the aggregation principle should only be applied where the activity’s commercial character is apparent. See Morrison, 529 U.S. at 611 n. 4, 120 S.Ct. 1740. Here it is not. Moreover, McCoy settled the fungibility issue less by looking at whether the item was one that could be freely exchanged or replaced (what one might consider to be the important characteristics of fungibility) and more by simply concluding that the photograph at issue in that case was “meant entirely for personal use, without ... any intention of exchanging it for other items of child pornography, or using it for any other economic or commercial reasons. Nor is there any reason to believe that [Rhonda McCoy] had any interest in acquiring pornographic depictions of other children.” 323 F.3d at 1122. Under these standards, the marijuana at issue in this case is similarly non-fungible, as its use is personal and the appellants do not seek to exchange it or to acquire marijuana from others in a market.
Therefore, we conclude that the first Morrison factor favors a finding that the CSA, as applied to the facts of this case, is unconstitutional under the Commerce Clause.5
b. Whether the Statute Contains Any Express Jurisdictional Element That Might Limit Its Reach
The second factor examines whether the statute contains a “jurisdictional hook” (i.e., limitation) that would limit the reach of the statute to a discrete set of cases that substantially affect interstate commerce. See McCoy, 323 F.3d at 1124. No such jurisdictional hook exists in relevant portions of the CSA. See County of Santa Cruz, 279 F.Supp.2d at 1209. Therefore, this factor favors a finding that Congress has exceeded its powers under the Commerce Clause.
c. Whether the Statute or Its Legislative History Contains Express Congressional Findings Regarding the Effects of the Regulated Activity Upon Interstate Commerce
Congress clearly made certain findings in the CSA regarding the effects of intra[1232]*1232state activity on interstate commerce. These findings do not specifically address the class of activities at issue here. Relevant findings include:
(4) Local distribution and possession of controlled substances contribute to swelling the interstate traffic in such substances.
(5) Controlled substances manufactured and distributed intrastate cannot be differentiated from controlled substances manufactured and distributed interstate. Thus, is it not feasible to distinguish, in terms of controls, between controlled substances manufactured and distributed interstate and controlled substances manufactured and distributed intrastate.
(6) Federal control of the intrastate incidents of the traffic in controlled substances is essential to the effective control of the interstate incidents of such traffic.
21 U.S.C. § 801. As noted above, supra note 4, these findings are primarily concerned with the trafficking or distribution of controlled substances. Nevertheless, they provide some evidence that intrastate possession of controlled substances may impact interstate commerce.
Therefore, the third factor weighs in favor of finding the CSA constitutional under the Commerce Clause. But it is worth reiterating two things in this respect. First, there is no indication that Congress was considering anything like the class of activities at issue here when it made its findings. The findings are not specific to marijuana, much less intrastate medicinal use of marijuana that is not bought or sold and the use of which is based on the recommendation of a physician. Common sense indicates that the findings related to this specific class of activities would be significantly different from the findings relating to the effect of drug trafficking, generally, on interstate commerce.6
Second, Morrison counsels courts to take congressional findings with a grain of salt.
[T]he existence of congressional findings is not sufficient, by itself, to sustain the constitutionality of Commerce Clause legislation. As we stated in Lopez, [sjimply because Congress may conclude that a particular activity substantially affects interstate commerce does not necessarily make it so. Rather, [wjhether particular operations affect interstate commerce sufficiently to come under the constitutional power of Congress to regulate them is ultimately a judicial rather than a legislative question, and can be settled finally only by this Court.
Morrison, 529 U.S. at 614, 120 S.Ct. 1740 (citations and quotation marks omitted). As noted above, it is not the existence of congressional findings, but rather the first and fourth factors — whether the statute regulates commerce or any sort of economic enterprise and whether the link between the regulated activity and a substantial effect on interstate commerce is “attenuated” — that are considered the most signifi[1233]*1233cant in this analysis.7 McCoy, 323 F.3d at 1119.
d. Whether the Link Between the Regulated Activity and a Substantial Effect on Interstate Commerce Is “Attenuated”
The final Morrison factor examines whether the link between the regulated activity and a substantial effect on interstate commerce is “attenuated.” The connections in this case are, indeed, attenuated. Presumably, the intrastate cultivation, possession and use of medical marijuana on the recommendation of a physician could, at the margins, have an effect on interstate commerce by reducing the demand for marijuana that is trafficked interstate. It is far from clear that such an effect would be substantial. The congressional findings provide no guidance in this respect, as they do not address the activities at issue in the present case. Although not binding, other judges that have looked at the specific question presented here have found that the connection is attenuated. As one of our colleagues wrote recently: “Medical marijuana, when grown locally for personal consumption, does not have any direct or obvious effect on interstate commerce. Federal efforts to regulate it considerably blur the distinction between what is national and what is local.” Conant v. Walters, 309 F.3d 629, 647 (9th Cir.2002) (Kozinski, J., concurring) (citation omitted). The district court in County of Santa Cruz also seriously questioned the strength of the link between such activities and interstate commerce. See County of Santa Cruz, 279 F.Supp.2d at 1209 (“The fourth factor — whether the link between [medical marijuana use] and a substantial affect on interstate commerce is attenuated — arguably favors Plaintiffs.”).8 Therefore, we conclude that this factor favors a finding that the CSA cannot constitutionally be applied to the class of activities at issue in this case.
[1234]*1234On the basis of our consideration of the four factors, we find that the CSA, as applied to the appellants, is likely unconstitutional. See McCoy, 323 F.3d at 1124 (“It is particularly important that in the field of criminal law enforcement, where state power is preeminent, national authority be limited to those areas in which interstate commerce is truly affected.... The police power is, essentially, reserved to the states, Morrison, 529 U.S. at 618, 120 S.Ct. 1740.... That principle must guide our review of Congress’s exercise of Commerce Clause power in the criminal law area.”); see also Morrison, 529 U.S. at 610, 120 S.Ct. 1740 (“[A] fair reading of Lo-pez shows that the noneconomic, criminal nature of the conduct at issue was central to our decision in that case.”).
Therefore, we find that the appellants have made a strong showing of the likelihood of success on the merits of their case.
B. Hardship and Public Interest Factors
The appellants contend that considerations of hardship and the public interest factors in this case require entry of the requested preliminary injunction.9 The district court found that,
[wjhile there is a public interest in the presumption of constitutional validity of congressional legislation, and while regulation of medicine by the FDA is also important, the Court finds that these interests wane in comparison with the public interests enumerated by plaintiffs and by the harm that they would suffer if denied medical marijuana.
The district court nevertheless denied the injunction given its findings regarding the merits of the case: “[Djespite the gravity of the plaintiffs’ need for medical cannabis, and despite the concrete interest of California to provide it for individuals like them, the Court is constrained from granting their request.” We find that the hardship and public interest factors tip sharply in the appellants’ favor.
There can be no doubt on the record as to the significant hardship that will be imposed on the patient-appellants if they are denied a preliminary injunction. The appellees do not dispute this. Instead, the appellees argue that Oakland Cannabis Buyers’ Cooperative precludes a finding that the public interest favors the appellants. The appellees quote: “[A] court sitting in equity cannot ignore the judgment of Congress, deliberately expressed in legislation.” Oakland Cannabis Buyers’ Coop., 532 U.S. at 497, 121 S.Ct. 1711 (quotation marks omitted). However, the relevant portion of that case dealt with what factors a district court may consider when fashioning injunctive relief. See id. at 495-98, 121 S.Ct. 1711. It did not address the constitutional challenges at issue here that call the very foundation of the CSA into question as applied to the class of activities at issue in this case. Therefore, the Court’s admonitions10 are not [1235]*1235relevant to this case. It would be absurd for the Court to have meant that, no matter how strong the showing of unconstitutionality, the statute must be enforced.
The appellees also contend that granting the appellants’ requested injunction would create a slippery slope as other plaintiffs seeking use of other schedule I controlled substances would bypass the statutory process established by Congress. The ap-pellees claim that the appellants’ proposed injunction therefore has the potential to significantly undermine the FDA drug approval process. Our holding is sufficiently narrow to avoid such concerns. Moreover, there is nothing contrary to the public interest in allowing individuals to seek relief from a statute that is likely unconstitutional as applied to them. The public interest of the state of California and its voters in the viability of the Compassionate Use Act also weighs against the appel-lees’ concerns. Cf. New State Ice Co. v. Liebmann, 285 U.S. 262, 311, 52 S.Ct. 371, 76 L.Ed. 747 (1932) (Brandéis, J., dissenting) (“It is one of the happy incidents of the federal system that a single courageous state may, if its citizens choose, serve as a laboratory; and try novel social and economic experiments without risk to the rest of the country.”). Finally, the appellees’ speculative slippery slope concern is weak in comparison to the real medical emergency facing the patient-appellants in this case.
CONCLUSION
For the reasons discussed above, we reverse the district court. We find that the appellants have demonstrated a strong likelihood of success on the merits. This conclusion, coupled with public interest considerations and the burden faced by the appellants if, contrary to California law, they are denied access to medicinal marijuana, warrants the entry of a preliminary injunction. We remand to the district court for entry of a preliminary injunction consistent with this opinion.
REVERSED AND REMANDED.