This is an appeal from a permanent injunction entered to protect First Amendment rights. The order enjoins the federal government from either revoking a physician’s license to prescribe controlled substances or conducting an investigation of a physician that might lead to such revocation, where the basis for the government’s action is solely the physician’s professional “recommendation” of the use of medical marijuana. The district court’s order and accompanying opinion are at Conant v. McCaffrey, 2000 WL 1281174 (N.D.Cal. Sept.7, 2000). The history of the litigation demonstrates that the injunction is not intended to limit the government’s ability to investigate doctors who aid and abet the actual distribution and possession of marijuana. 21 U.S.C. § 841(a). The government has not provided any empirical evidence to demonstrate that this injunction interferes with or threatens to interfere with any legitimate law enforcement activities. Nor is there any evidence that the similarly phrased preliminary injunction that preceded this injunction, Conant v. McCaffrey, 172 F.R.D. 681 (N.D.Cal.1997), which the government did not appeal, interfered with law enforcement. The district court, on the other hand, explained convincingly when it entered both the earlier preliminary injunction and this permanent injunction, how the government’s professed enforcement policy threatens to interfere with expression protected by the First Amendment. We therefore affirm.
I. The Federal Marijuana Policy
The federal government promulgated its policy in 1996 in response to initiatives passed in both Arizona and California decriminalizing the use of marijuana for limited medical purposes and immunizing physicians from prosecution under state law for the “recommendation or approval” of using marijuana for medical purposes. See Cal. Health & Safety Code § 11362.5. The federal policy declared that a doctor’s “action of recommending or prescribing Schedule I controlled substances is not consistent with the ‘public interest’ (as that phrase is used in the federal Controlled Substances Act)” and that such action would lead to revocation of the physician’s registration to prescribe controlled substances.1 The policy relies on the definition of “public interest” contained in 21 U.S.C. § 823(f), which provides:
In determining the public interest, the following factors shall be considered: (1) The recommendation of the appropriate State licensing board or professional disciplinary authority. (2) The applicant’s experience in dispensing, or conducting research with respect to controlled substances. (3) The applicant’s conviction record under Federal or State laws re*633lating to the manufacture, distribution, or dispensing of controlled substances. (4) Compliance with applicable State, Federal, or local laws relating to controlled substances. (5) Such other conduct which may threaten the public health and safety.
The policy also said that the DOJ and the HHS would send a letter to practitioner associations and licensing boards informing those groups of the policy. The federal agencies sent a letter two months later to national, state, and local practitioner associations outlining the Administration’s position (“Medical Leader Letter”). The Medical Leader Letter cautioned that physicians who “intentionally provide their patients with oral or written statements in order to enable them to obtain controlled substances in violation of federal law ... risk revocation of their DEA prescription authority.”
II. Litigation History
Plaintiffs are patients suffering from serious illnesses, physicians licensed to practice in California who treat patients with serious illnesses, a patient’s organization, and a physician’s organization. The patient organization is Being Alive: People with HIV/AIDS Action Coalition, Inc. The physician’s organization is the Bay Area Physicians for Human Rights. Plaintiffs filed this action in early 1997 to enjoin enforcement of the government policy insofar as it threatened to punish physicians for communicating with their patients about the medical use of marijuana. The case was originally assigned to District Judge Fern Smith, who presided over the case for more than two years. After Judge Smith received the parties’ briefs, she issued a temporary restraining order, certified a plaintiff class, denied the government’s motion to dismiss, issued a preliminary injunction, awarded interim attorney’s fees to plaintiffs, and set the briefing schedule for discovery.
Judge Smith entered the preliminary injunction on April 30, 1997. It provided that the government “may not take administrative action against physicians for recommending marijuana unless the government in good faith believes that it has substantial evidence” that the physician aided and abetted the purchase, cultivation, or possession of marijuana, 18 U.S.C. § 2, or engaged in a conspiracy to cultivate, distribute, or possess marijuana, 21 U.S.C. § 846. Id. at 700. Judge Smith specifically enjoined the “defendants, their agents, employees, assigns, and all persons acting in concert or participating with them, from threatening or prosecuting physicians, [or] revoking their licenses ... based upon conduct relating to medical marijuana that does not rise to the level of a criminal offense.” Id. at 701. The preliminary injunction covered not only “recommendations,” but also “non-criminal activity related to those recommendations, such as providing a copy of a patient’s medical chart to that patient or testifying in court regarding a recommendation that a patient use marijuana to treat an illness.” Id. at 701 n. 8.
The government did not appeal the preliminary injunction, and it remained in effect after the case was transferred more than two years later to Judge Alsup on August 19, 1999. Judge Alsup in turn granted a motion to modify the plaintiff class, held a hearing on motions for summary judgment, granted in part and denied in part the cross-motions for summary judgment, dissolved the preliminary injunction, and entered a permanent injunction. The class was modified to include only those patients suffering from specific symptoms related to certain illnesses and physicians who treat such patients. The permanent injunction appears *634to be functionally the same as the preliminary injunction that Judge Smith originally entered. It provides that the government is permanently enjoined from:
(i) revoking any physician class member’s DEA registration merely because the doctor makes a recommendation for the use of medical marijuana based on a sincere medical judgment and (ii) from initiating any investigation solely on that ground. The injunction should apply whether or not the doctor anticipates that the patient will, in turn, use his or her recommendation to obtain marijuana in violation of federal law.
Conant, 2000 WL 1281174, at *16.
In explaining his reasons for entering the injunction, Judge Alsup pointed out that there was substantial agreement between the parties as to what doctors could and could not do under the federal law. Id. at *11. The government agreed with plaintiffs that revocation of a license was not authorized where a doctor merely discussed the pros and eons of marijuana use. Id. The court went on to observe that the plaintiffs agreed with the government that a doctor who actually prescribes or dispenses marijuana violates federal law. The fundamental disagreement between the parties concerned the extent to which the federal government could regulate doctor-patient communications without interfering with First Amendment interests. Id. This appeal followed.
III. Discussion
It is important at the outset to observe that this case has been litigated independently of contemporaneous litigation concerning whether federal law exempts from prosecution the dispensing of marijuana in cases of medical necessity. The Supreme Court in that litigation eventually held that it does not, reversing this court. See United States v. Oakland Cannabis Buyers’ Coop., 532 U.S. 483, 121 S.Ct. 1711, 149 L.Ed.2d 722 (2001), rev’g United States v. Oakland Cannabis Buyers’ Coop., 190 F.3d 1109 (9th Cir.1999). When the district court entered the permanent injunction in this case, it pointed out that it was doing so without regard to this Circuit’s decision in the Oakland Cannabis litigation. Conant, 2000 WL 1281174, at *15 n. 7.
The dispute in the district court in this case focused on the government’s policy of investigating doctors or initiating proceedings against doctors only because they “recommend” the use of marijuana. While the government urged that such recommendations lead to illegal use, the district court concluded that there are many legitimate responses to a recommendation of marijuana by a doctor to a patient. There are strong examples in the district court’s opinion supporting the district court’s conclusion. For example, the doctor could seek to place the patient in a federally approved, experimental marijuana-therapy program. Id. at *15. Alternatively, the patient upon receiving the recommendation could petition the government to change the law. Id. at *14. By chilling doctors’ ability to recommend marijuana to a patient, the district court held that the prohibition compromises a patient’s meaningful participation in public discourse. Id. The district court stated:
Petitioning Congress or federal agencies for redress of a grievance or a change in policy is a time-honored tradition. In the marketplace of ideas, few questions are more deserving of free-speech protection than whether regulations affecting health and welfare are sound public policy. In the debate, perhaps the status quo will (and should) endure. But patients and physicians are certainly entitled to urge their view. To hold that physicians are barred from communicat*635ing to patients sincere medical judgments would disable patients from understanding their own situations well enough to participate in the debate. As the government concedes, ... many patients depend upon discussions with their physicians as their primary or only source of sound medical information. Without open communication with their physicians, patients would fall silent and appear uninformed. The ability of patients to participate meaningfully in the public discourse would be compromised.
Id.
On appeal, the government first argues that the “recommendation” that the injunction may protect is analogous to a “prescription” of a controlled substance, which federal law clearly bars. We believe this characterizes the injunction as sweeping more broadly than it was intended or than as properly interpreted. If, in making the recommendation, the physician intends for the patient to use it as the means for obtaining marijuana, as a prescription is used as a means for a patient to obtain a controlled substance, then a physician would be guilty of aiding and abetting the violation of federal law. That, the injunction is intended to avoid. Indeed the predecessor preliminary injunction spelled out what the injunction did not bar; it did not enjoin the government from prosecuting physicians when government officials in good faith believe that they have “probable cause to charge under the federal aiding and abetting and/or conspiracy statutes.” 172 F.R.D. at 701.
The plaintiffs themselves interpret the injunction narrowly, stating in their brief before this Court that, “the lower court fashioned an injunction with a clear line between protected medical speech and illegal conduct.” They characterize the injunction as protecting “the dispensing of information,” not the dispensing of controlled substances, and therefore assert that the injunction does not contravene or undermine federal law.
As Judge Smith noted in the preliminary injunction order, conviction of aiding and abetting requires proof that the defendant “associate^] himself with the venture, that he participate^] in it as something that he wishe[d] to bring about, that he [sought] by his actions to make it succeed.” 172 F.R.D. at 700 (quoting Cent. Bank of Denver, N.A. v. First Interstate Bank of Denver, N.A., 511 U.S. 164, 190, 114 S.Ct. 1439, 128 L.Ed.2d 119 (1994) (internal quotation marks and citation omitted)). This is an accurate statement of the law. We have explained that a conviction of aiding and abetting requires the government to prove four elements: “(1) that the accused had the specific intent to facilitate the commission of a crime by another, (2) that the accused had the requisite intent of the underlying substantive offense, (3) that the accused assisted or participated in the commission of the underlying substantive offense, and (4) that someone committed the underlying substantive offense.” See United States v. Gaskins, 849 F.2d 454, 459 (9th Cir.1988). The district court also noted that conspiracy requires that a defendant make “an agreement to accomplish an illegal objective and [that he] knows of the illegal objective and intends to help accomplish it.” 172 F.R.D. at 700-01 (citing United States v. Gil, 58 F.3d 1414, 1423 & n. 5 (9th Cir.1995)).
The government on appeal stresses that the permanent injunction applies “whether or not the doctor anticipates that the patient will, in turn, use his or her recommendation to obtain marijuana in violation of federal law,” and suggests that the injunction thus protects criminal conduct. A doctor’s anticipation of patient conduct, however, does not translate into *636aiding and abetting, or conspiracy. A doctor would aid and abet by acting with the specific intent to provide a patient with the means to acquire marijuana. See Gaskins, 849 F.2d at 459. Similarly, a conspiracy would require that a doctor have knowledge that a patient intends to acquire marijuana, agree to help the patient acquire marijuana, and intend to help the patient acquire marijuana. See Gil, 58 F.3d at 1423. Holding doctors responsible for whatever conduct the doctor could anticipate a patient might engage in after leaving the doctor’s office is simply beyond the scope of either conspiracy or aiding and abetting.
The government also focuses on the injunction’s bar against “investigating” on the basis of speech protected by the First Amendment and points to the broad discretion enjoyed by executive agencies in investigating suspected criminal misconduct. The government relies on language in the permanent injunction that differs from the exact language in the preliminary injunction. The permanent injunction order enjoins the government “from initiating any investigation solely on” the basis of “a recommendation for the use of medical marijuana based on a sincere medical judgment.” Conant, 2000 WL 1281174, at *16. The preliminary injunction order provided that “the government may not take administrative action against physicians for recommending marijuana unless the government in good faith believes that it has substantial evidence of [conspiracy or aiding and abetting].” 172 F.R.D. at 701.
The government, however, has never argued that the two injunctive orders differ in any material way. Because we read the permanent injunction as enjoining essentially the 13 same conduct as the preliminary injunction, we interpret this portion of the permanent injunction to mean only that the government may not initiate an investigation of a physician solely on the basis of a recommendation of marijuana within a bona fide doctor-patient relationship, unless the government in good faith believes that it has substantial evidence of criminal conduct. Because a doctor’s recommendation does not itself constitute illegal conduct, the portion of the injunction barring investigations solely on that basis does not interfere with the federal government’s ability to enforce its laws.
The government policy does, however, strike at core First Amendment interests of doctors and patients. An integral component of the practice of medicine is the communication between a doctor and a patient. Physicians must be able to speak frankly and openly to patients. That need has been recognized by the courts through the application of the common law doctor-patient privilege. See Fed.R.Evid. 501.
The doctor-patient privilege reflects “the imperative need for confidence and trust” inherent in the doctor-patient relationship and recognizes that “a physician must know all that a patient can articulate in order to identify and to treat disease; barriers to full disclosure would impair diagnosis and treatment.” Trammel v. United States, 445 U.S. 40, 51, 100 S.Ct. 906, 63 L.Ed.2d 186 (1980). The Supreme Court has recognized that physician speech is entitled to First Amendment protection because of the significance of the doctor-patient relationship. See Planned Parenthood of Southeastern Pennsylvania v. Casey, 505 U.S. 833, 884, 112 S.Ct. 2791, 120 L.Ed.2d 674 (1992) (plurality) (recognizing physician’s First Amendment right not to speak); Rust v. Sullivan, 500 U.S. 173, 200, 111 S.Ct. 1759, 114 L.Ed.2d 233 (1991) (noting that regulations on physician speech may “impinge upon the doctor-patient relationship”).
*637This Court has also recognized the core First Amendment values of the doctor-patient relationship. In Nat’l Ass’n for the Advancement of Psychoanalysis v. California Bd. of Psychology, 228 F.3d 1043 (9th Cir.2000), we recognized that communication that occurs during psychoanalysis is entitled to First Amendment protection. Id. at 1054. We upheld California’s mental health licensing laws that determined when individuals qualified as mental health professionals against a First Amendment challenge. Id. at 1053-56. Finding the laws content-neutral, we noted that California did not attempt to “dictate the content of what is said in therapy” and did not prevent licensed therapists from utilizing particular “psychoanalytical methods.” Id. at 1055-56.
Being a member of a regulated profession does not, as the government suggests, result in a surrender of First Amendment rights. See Thomas v. Collins, 323 U.S. 516, 531, 65 S.Ct. 315, 89 L.Ed. 430 (1945) (“the rights of free speech and a free press are not confined to any field of human interest”). To the contrary, professional speech may be entitled to “the strongest protection our Constitution has to offer.” Florida Bar v. Went For It, Inc., 515 U.S. 618, 634, 115 S.Ct. 2371, 132 L.Ed.2d 541 (1995). Even commercial speech by professionals is entitled to First Amendment protection. See Bates v. Arizona, 433 U.S. 350, 382-83, 97 S.Ct. 2691, 53 L.Ed.2d 810 (1977). Attorneys have rights to speak freely subject only to the government regulating with “narrow specificity.” NAACP v. Button, 371 U.S. 415, 433, 438-39, 83 S.Ct. 328, 9 L.Ed.2d 405 (1963).
In its most recent pronouncement on regulating speech about controlled substances, Thompson v. Western States Medical Ctr., 535 U.S. 357, 122 S.Ct. 1497, 152 L.Ed.2d 563 (2002), the Supreme Court found that provisions in the Food and Drug Modernization Act of 1997 that restricted physicians and pharmacists from advertising compounding drugs violated the First Amendment. Id. at 1500. The Court refused to make the “questionable assumption that doctors would prescribe unnecessary medications” and rejected the government’s argument that “people would make bad decisions if given truthful information about compounded drugs.” Id. at 1507. The federal government argues in this case that a doctor-patient discussion about marijuana might lead the patient to make a bad decision, essentially asking us to accept the same assumption rejected by the Court in Thompson. Id. We will not do so. Instead, we take note of the Supreme Court’s admonition in Thompson: “If the First Amendment means anything, it means that regulating speech must be a last — not first — resort. Yet here it seems to have been the first strategy the Government thought to try.” Id.
The government’s policy in this case seeks to punish physicians on the basis of the content of doctor-patient communications. Only doctor-patient conversations that include discussions of the medical use of marijuana trigger the policy. Moreover, the policy does not merely prohibit the discussion of marijuana; it condemns expression of a particular viewpoint, i.e., that medical marijuana would likely help a specific patient. Such condemnation of particular views is especially troubling in the First Amendment context. “When the government targets not subject matter but particular views taken by speakers on a subject, the violation of the First Amendment is all the more blatant.” Rosenberger v. Rector, 515 U.S. 819, 829, 115 S.Ct. 2510, 132 L.Ed.2d 700 (1995). Indeed, even content-based restrictions on speech are “presumptively invalid.” *638R.A.V. v. St. Paul, 505 U.S. 377, 382, 112 S.Ct. 2538, 120 L.Ed.2d 305 (1992).
The government’s policy is materially similar to the limitation struck down in Legal Services Corp. v. Velazquez, 531 U.S. 533, 121 S.Ct. 1043, 149 L.Ed.2d 63 (2001), that prevented attorneys from “present[ing] all the reasonable and well-grounded arguments necessary for proper resolution of the case.” 531 U.S. at 545, 121 S.Ct. 1043. In Velazquez, a government restriction prevented legal assistance organizations receiving federal funds from challenging existing welfare laws. Id. at 537-38, 121 S.Ct. 1043. Like the limitation in Velazquez, the government’s policy here “alter[s] the traditional role” of medical professionals by “prohibit[ing] speech necessary to the proper functioning of those systems.” Id. at 544, 121 S.Ct. 1043.
The government relies upon Rust and Casey to support its position in this case. Rust, 500 U.S. 173, 111 S.Ct. 1759, 114 L.Ed.2d 233; Casey, 505 U.S. 833, 112 S.Ct. 2791, 120 L.Ed.2d 674. However, those cases did not uphold restrictions on speech itself. Rust upheld restrictions on federal funding for certain types of activity, including abortion counseling, referral, or advocacy. See Rust, 500 U.S. at 179-80, 111 S.Ct. 1759. In Casey, a plurality of the Court upheld Pennsylvania’s requirement that physicians’ advice to patients include information about the health risks associated with an abortion and that physicians provide information about alternatives to abortion. 505 U.S. at 883-84, 112 S.Ct. 2791. The plurality noted that physicians did not have to comply if they had a reasonable belief that the information would have a “severely adverse effect on the physical or mental health of the patient,” and thus the statute did not “prevent the physician from exercising his or her medical judgment.” Id. The government’s policy in this case does precisely that.
The government seeks to justify its policy by claiming that a doctor’s “recommendation” of marijuana may encourage illegal conduct by the patient, which is not unlike the argument made before, and rejected by, the Supreme Court in a recent First Amendment case. See Ashcroft v. Free Speech Coalition, 535 U.S. 234, 122 S.Ct. 1389, 1403, 152 L.Ed.2d 403 (2002). In Free Speech Coalition, the government defended the Child Pornography Prosecution Act of 1996 by arguing that, although virtual child pornography does not harm children in the production process, it threatens them in “other, less direct, ways.” Id. at 1397. For example, the government argued pedophiles might use such virtual images to encourage children to participate in sexual activity. Id. The Supreme Court rejected such justifications, holding that the potential harms were too attenuated from the proscribed speech. “Without a significantly stronger, more direct connection, the Government may not prohibit speech on the ground that it may encourage ... illegal conduct.” Id. at 1403. The government’s argument in this case mirrors the argument rejected in Free Speech Coalition.
The government also relies on a case in which a district court refused to order an injunction against this federal drug policy. See Pearson v. McCaffrey, 139 F.Supp.2d 113, 125 (D.D.C.2001). The court did so, however, because the plaintiffs in that case did not factually support their claim that the policy chilled their speech. See id. at 120. In this case, the record is replete with examples of doctors who claim a right to explain the medical benefits of marijuana to patients and whose exercise of that right has been chilled by the threat of federal investigation. The government even stipulated in the district court that a *639“reasonable physician would have a genuine fear of losing his or her DEA registration to dispense controlled substances if that physician were to recommend marijuana to his or her patients.”
To survive First Amendment scrutiny, the government’s policy must have the requisite “narrow specificity.” See Button, 371 U.S. at 433, 83 S.Ct. 328. Throughout this litigation, the government has been unable to articulate exactly what speech is proscribed, describing it only in terms of speech the patient believes to be a recommendation of marijuana. Thus, whether a doctor-patient discussion of medical marijuana constitutes a “recommendation” depends largely on the meaning the patient attributes to the doctor’s words. This is not permissible under the First Amendment. See Thomas v. Collins, 323 U.S. 516, 535, 65 S.Ct. 315, 89 L.Ed. 430 (1945). In Thomas, the court struck down a state statute that failed to make a clear distinction between union membership, solicitation, and mere “discussion, laudation, [or] general advocacy.” The distinction rested instead on the meaning the listeners attributed to spoken words. Id. The government’s policy, like the statute in Thomas, leaves doctors and patients “no security for free discussion.” Id. As Judge Smith appropriately noted in granting the preliminary injunction, “when faced with the fickle iterations of the government’s policy, physicians have been forced to suppress speech that would not rise to the level of that which the government constitutionally may prohibit.” 172 F.R.D. at 696.
Our decision is consistent with principles of federalism that have left states as the primary regulators of professional conduct. See Whalen v. Roe, 429 U.S. 589, 603 n. 30, 97 S.Ct. 869, 51 L.Ed.2d 64 (1977) (recognizing states’ broad police powers to regulate the administration of drugs by health professionals); Linder v. United States, 268 U.S. 5, 18, 45 S.Ct. 446, 69 L.Ed. 819 (1925) (“direct control of medical practice in the states is beyond the power of the federal government”). We must “show[ ] respect for the sovereign States that comprise our Federal Union. That respect 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.” Oakland Cannabis, 532 U.S. at 501, 121 S.Ct. 1711 (Stevens, J., concurring) (internal quotation marks omitted).
For all of the foregoing reasons, we affirm the district court’s order entering a permanent injunction.
AFFIRMED.
. The policy was entitled "The Administration's Response to the Passage of California Proposition 215 and Arizona Proposition 200” and was released on December 30, 1996, by Barry R. McCaffrey, the Director of the Office of National Drug Control Policy ("ONDCP”) at the time. The Administration’s Response was promulgated by an inter-agency working group that included the ONDCP; the Drug Enforcement Administration ("DEA”); the Department of Justice ("DOJ”); the Department of Health and Human Services ("HHS”); the Nuclear Regulatory Commission; and the Departments of Treasury, Defense, Transportation, and Education.