FEDERAL TRADE COMMISSION, PETITIONER V. INDIANA FEDERATION OF DENTISTS No. 84-1809 In the Supreme Court of the United States October Term, 1985 On Writ of Certiorari to the United States Court of Appeals for the Seventh Circuit Reply Brief for the Federal Trade Commission We demonstrated in our opening brief that the court of appeals misapprehended and grossly misapplied the substantial evidence standard in overturning the Federal Trade Commission's determination that respondent engaged in an unreasonable restraint of trade. The conspiracy led by respondent to prevent dentists from providing x-rays to insurers plainly reduced competition among dentists, insulating dentists from market forces that create incentives for compliance with insurers' cost containment efforts. Respondent's answering brief and the briefs filed by amici curiae in support of respondent /1/ do not refute our position. 1. In our opening brief, we observed that this case does not present an occasion for the Court to determine the manner in which antitrust analysis should take account of claims that a restraint of trade is justified on the ground that it promotes quality health care. That question does not arise here because respondent failed to supply any factual support for its claim that the ban upon submission of x-rays to insurers was necessary to maintain quality dental care. See FTC Br. 36-43. All of the amici supporting respondent agree with our conclusion. See AMA Br. 24; ADA Br. 13; PSAM Br. 2; ACR Br. 2. They concede, either explicitly or implicitly, that there simply is no factual support for respondent's quality of care claim. /2/ Respondent alone contends (Br. 19-26) that this Court should hold that the conspiracy did not violate the antitrust laws because it promoted quality dental care. However, the Commission correctly concluded (Pet. App. 91a-96a) that the conspiracy was not justified by such quality of care considerations. /3/ Respondent argues (Br. 26) that its conspiracy was necessary to prevent insurers from using x-rays to make medical diagnoses, but, as we discussed in our opening brief (at 39-40), the diagnosis is made by the treating dentist; the insurer simply evaluates a claim for reimbursement. The patient at all times remains free to select the course of treatment that he desires. Moreover, an insurer denies a claim or awards less than full reimbursement only pursuant to a recommendation by a licensed dentist, who may obtain any information in addition to the x-rays that he deems necessary to form a professional judgment regarding the appropriate treatment (Pet. App. 92a). Thus, there is no support whatsoever for respondent's claim that insurers make medical diagnoses or that insurers' use of x-rays results in inadequate dental care. /4/ Respondent attempts to bolster its claim by citing (Br. 25-26) assorted bulletins, informal pronouncements, and letters issued by employees of various Indiana state agencies as proof that insurance carriers violated Indiana law by using dental x-rays to determine insurance benefits. In considering this same "evidence," however, the Commission found that "none of the documents" cited by IFD supports the proposition that state law forbade insurers from using dental x-rays to make health insurance benefits determinations. Pet. App. 102a; see also id. at 98a-102a. /5/ Moreover, even if one could imagine an Indiana policy barring an insurer from using x-rays to determine its contractual liability to pay claims, enforcement of such a policy surely would rest with the appropriate state officials. Respondent has not attempted to explain why the antitrust laws should permit ad hoc enforcement of such a state policy through a conspiracy among competitors motivated in large part by their own economic interests. Cf. Fashion Originators' Guild, Inc. v. FTC, 312 U.S. 457 (1941). In view of the lack of evidence supporting IFD's proffered justification for the conspiracy, the court of appeals erred in premising its analysis upon "the fact that the conduct of the IFD member dentists is not designed to drive out competitors but to promote a legal, moral, and ethical policy of quality and proper dental care" (Pet. App. 33a n.15). IFD simply failed to make any threshold showing that its conduct could be justified on ehtical grounds. /6/ 2. The Commission analyzed the conspiracy led by respondent under the rule of reason and found that the conspiracy constituted an unreasonable restraint of trade. We showed in our opening brief (at 23-36) that this determination plainly is supported by substantial record evidence. a. Respondent first contends (Br. 19, 28) that the Commission failed to engage in the analysis necessary to conclude that the conspiracy is unlawful under the rule of reason. The AMA elaborates on this contention, arguing that there exist three mutually exclusive modes of analysis that may be applied in evaluating alleged restraints of trade -- per se analysis, "truncated" or "limited" rule of reason analysis, and "full" or "traditional" rule of reason analysis -- and that the Commission's decision cannot be sustained under either "limited" or "full" rule of reason analysis. AMA Br. 10-14, 18-30. This argument is based upon a misunderstanding of the standards governing analysis under the rule of reason. The AMA concedes (Br. 12 n.7) that this Court has not held that there are three distinct standards for analyzing restraints of trade. In fact, the Court has referred to two categories of analysis -- per se rules and the rule of reason (see National Society of Professional Engineers v. United States, 435 U.S. 679, 687-692 (1978)), and noted that "there is often no bright line separating per se from Rule of Reason analysis" (NCAA v. Board of Regents, No. 83-271 (June 27, 1984), slip op. 17 n.26). Indeed, several commentators have spoken of a single standard under which restraints are measured on a continuum of reasonableness ranging from inherently anticompetitive at one end to procompetitive at the other. /7/ Rule of reason analysis is a flexible approach to determining the "reasonableness" of an unending variety of commercial practices that differ greatly in their complexity, purpose, and effect. In some situations, a rule of reason inquiry may entail "an incredibly complicated and prolonged economic investigation into the entire history of the industry involved, as well as related industries, in an effort to determine at large whether a particular restraint has been unreasonable" (Northern Pac. Ry. v. United States, 356 U.S. 1, 5 (1958)). In other circumstances, the rule of reason may allow summary condemnation of an agreement that inherently restrains trade and offers no redeeming procompetitive benefits. NCAA v. Board of Regents, slip op. 20-21; Professional Engineers, 435 U.S. at 692-693; see also United States v. Philadelphia National Bank, 374 U.S. 321, 362 (1963) ("in any (rule of reason) case in which it is possible * * * to simplify the test of illegality, the courts ought to do so in the interest of sound and practical judicial administration"). The "full rule of reason" and "truncated rule of reason" cited by respondent and the AMA thus are not different tests; they are convenient labels that describe the amount of investigation required "to form a judgment about the competitive significance of (a) restraint." Professional Engineers, 435 U.S. at 692; see also NCAA v. Board of Regents, slip op. 16. /8/ The AMA faults the Commission for failing to invoke by name the "truncated rule of reason" (Br. 8-9, 19, 25-26). However, the correctness of the Commission's decision cannot depend upon whether it applied a particular label to its analysis, especially where the basic analytic approach is the same. The question instead is whether the Commission's inquiry was sufficient to ascertain the competitive effect of the restraint. /9/ For example, in NCAA v. Board of Regents, the Court applied a "limited" rule of reason analysis (slip op. 20-26), but never expressly referred to such a standard. The Court stated only that it was analyzing the practices at issue "under the Rule of Reason" because a "fair evaluation of their competitive character requires consideration of the * * * justifications for the restraints" (id. at 16). The Court identified the threat to competition posed by the challenged practices -- limiting price competition and output, and frustrating consumer preference -- and declared the practices unlawful because they were not justified by any valid procompetitive effect (id. at 20-33). The Commission applied a similar rule of reason analysis here, identifying the threat to competition and considering proffered justifications. As we discussed in our opening brief (at 25-26), the conspiracy at issue in this case resembles attempts by horizontal competitors to dictate the terms upon which they will deal with others (Paramount Famous Lasky Corp. v. United States, 282 U.S. 30 (1930)) and competitors' efforts to restrict the flow of price-related information (Professional Engineers, supra). Since the facts contained in the record before the Commission indicated that the agreement at issue here had a similar anticompetitive effect (see FTC Br. 23-36; pages 11-15, infra), the Commission correctly concluded that no elaborate analysis was necessary to find that -- absent any procompetitive justification -- the agreement constituted an unreasonable restraint of trade (Pet. App. 85a-86a). Respondent argues that this analysis is incorrect because Professional Engineers involved an "absolute ban" on price information while this case concerns only a "very limited refusal to cooperate with only one aspect of the insurers' claims processing procedures." IFD Br. 23; see also AMA Br. 30. In Professional Engineers, the conspirators agreed to withhold information about prices until a purchaser tentatively selected an engineer-seller on the basis of reputation or other factors. After an engineer was selected, however, the purchaser could negotiate the price to be charged and select a different engineer if the negotiated price was unacceptable (435 U.S. at 684 n.6). The restraint thus affected the dissemination of price information only to a limited extent; it required engineers to withhold such information from buyers at the time and in the form buyers deemed price information most desirable in order to further their goal of minimizing the cost of engineering services. Here, insurers -- who ultimately pay for dental services -- have concluded that, in order to carry out cost containment policies that were sought by consumers, they require x-rays both to predetermine benefits and decide whether to authorize payment for services already rendered. The conspiracy denies them this important method of obtaining the price-related information they need to review patient claims and efficiently identify claims that require further consideration. Access to x-rays is necessary so that insurers may pay only for the least expensive but adequate care, and avoid paying for unnecessary services. While the conspiracy here is not "price fixing as such, no elaborate industry analysis is required to demonstrate the anticompetitive character of such an agreement" (Professional Engineers, 435 U.S. at 692). Thus, the Commission correctly concluded that a more elaborately detailed inquiry was not needed to determine that the conspiracy led by respondent exerted an anticompetitive effect warranting condemnation under the antitrust laws. /10/ b. Respondent claims (Br. 27-35) that the record does not contain facts necessary to support the Commission's determination, but the record is replete with evidence demonstrating that the Commission correctly applied the legal analysis discussed above (see pages 5-10, supra) to conclude that the conspiracy led by respondent constituted an unreasonable restraint of trade. IFD does not dispute that, e.g., (1) the statewide Indiana Dental Association and its members, who comprised 85% of licensed Indiana dentists, engaged in a collective refusal to submit x-rays to insurers for claims review; /11/ (2) by early 1975 most dentists in Indiana were refusing to submit x-rays to insurers; /12/ (3) IFD in large part was formed to continue this concerted action when IDA's enthusiasm for the consiracy waned because of concern about antitrust liability; /13/ (4) IFD's first president acknowledged dentists' strong economic interest in withholding x-rays when he was a leader of the IDA phase of the conspiracy; /14/ (5) one of IFD's first actions was to adopt a work rule barring IFD members from sending dental x-rays to insurers who requested x-rays for purposes of claims review and cost containment; /15/ (6) a solid majority of dentists practicing in the area covered by IFD's Anderson and Lafayette chapters were members of IFD; /16/ and (7) IFD members refused to send x-rays to insurers. /17/ These facts surely are sufficient to show that IFD's conspiracy had an anticompetitive effect. IFD first argues (Br. 28-30) that there is no evidence in the record to support the Commission's conclusion that p oviding x-rays to insurers was an element of competition among dentists. In fact, as we demonstrated in our opening brief (at 27-31), documentary evidence clearly establishes that dentists were aware of competitive pressure to supply x-rays to insurers and that dentists in fact competed for patients with respect to this aspect of cooperation with insurers. /18/ IFD next argues (Br. 30-32) that the Commission's determination cannot be upheld because the Commission did not describe with precision the geographic market affected by the conspiracy. IFD complains that the record does not include "evidence regarding the number or percentage of insured patients who patronize IFD members and, thus, no empirical evidence of patient demand" (IFD Br. 29) and that "to establish the contours of relevant geographic markets * * * (n)either a static nor a dynamic analysis was attempted, and no patient flow data was ever introduced" (id. at 30 (footnote omitted)). IFD's complaints are unfounded. The types of evidence identified by IFD would be probative in defining a relevant market, but such evidence is not the only means of determining that dentists compete among themselves with respect to submission of patient claims information to insurers or that an agreement by dentists not to compete with respect to x-ray submission affects competition in the communities in which the dentists practice. "(W)here the anticompetitive effects of conduct can be ascertained through means short of extensive market analysis, and where no countervailing competitive virtues are evident, a lengthy analysis of market power is not necessary.'" NCAA v. Board of Regents, slip op. 23-24 n.42; see also Professional Engineers, 435 U.S. at 695. The Commission found that IFD's conduct was the continuation of a statewide conspiracy begun by IDA, the state dental association, and that IDA and IFD had the market power to make their boycott effective, with IDA's membership including 85% of all dentists licensed in Indiana, most of whom participated in the boycott (Pet. App. 151a-152a, 172a-175a). /19/ In continuing IDA's statewide conspiracy, IFD achieved substantial majority participation among the practicing dentists in Madison County and in the area covered by its Lafayette Chapter. Pet. App. 39a-40a, 84a-85a; J.A. 124; see FTC Br. 32 n.24. Given the broad scope of the initial boycott and its evident economic purposes and effect, no further analysis of the geographic market was required to determine that IFD's conduct had an impermissible anticompetitive effect. See NCAA v. Board of Regents, slip op. 23-24 & n.42; compare Paramount Famous Lasky Corp. v. United States, 282 U.S. at 44. Finally, IFD argues (Br. 32) that "the Commission wholly failed to demonstrate any adverse impact on competition or consumers." IFD complains that "(t)he record * * * fails to reflect evidence of patient complaints, the number of insured patients involved, or the avilability or use of alternatives" (id. at 33). However, IFD ignores the ample record evidence establishing that the conspiracy had an adverse effect upon both patients and insurers. The evidence demonstrates that (1) IFD and IDA possessed market power, (2) the conspiracy was motivated by economic purposes, (3) dentists did stop competing to a substantial degree with respect to their policy of submitting x-rays to insurers, (4) insurers incurred substantial costs as a result of the collective refusal to submit x-rays, and (5) patients were unable to engage the services of dentists who would submit x-rays and thus lost the benefit of their insurance contracts. See FTC Br. 9-12. This evidence is more than sufficient to support the Commission's finding of an unlawful anticompetitive effect. See American Textile Manufacturers Institute v. Donovan, 452 U.S. 490, 522-523 (1981); Universal Camera Corp. v. NLRB, 340 U.S. 474, 477 (1951). /20/ For the foregoing reasons and the reasons stated in our opening brief, the judgment of the court of appeals should be reversed and the case remanded with instructions that the court affirm and enforce the order of the Commission. Respectfully submitted. CHARLES FRIED Solicitor General MARCY J.K. TIFFANY Acting General Counsel Federal Trade Commission MARCH 1986 /1/ The following entities have submitted briefs amicus curiae supporting IFD: the American Dental Association (ADA); the American Medical Association (AMA), the Physicians and Surgeons Association of Massachusetts (PSAM); and the American College of Radiology (ACR). We note that the AMA mistakenly asserts that this case was remanded to the Commission by the court of appeals (Br. 20); the court merely vacated the Commission's order and awarded costs to IFD (Pet. App. 51a). /2/ For example, the AMA states that IFD "apparently did not present any evidence that its practices were genuinely intended to promote patient care or that they had that effect" (AMA Br. 24). It is particularly noteworthy that the American Dental Association makes no attempt to argue that IFD's conspiracy was in any way related to maintaining the quality of patient dental care, despite the ADA's obvious familiarity with the relevant medical issues. /3/ Respondent claims (Br. 17) that our dispute is "with the (court of appeals') consideration of 'quality of care' factors in applying the rule of reason," but the court of appeals did not expressly overturn -- or even address -- the Commission's factual finding that respondent's conspiracy could not be justified as necessary to promote quality dental care (see FTC Br. 37). /4/ Contrary to respondent's assertion (Br. 26), we do not contend that health care providers must produce a "body count" before health and safety justifications may be considered in antitrust analysis. At the minimum, however, a party must produce at least some evidence supporting an assertion that a challenged restraint serves to promote health or safety before the relevance of such a justification need be addressed. Respondent simply has not supplied any evidence that insurers' use of x-rays in benefits determinations results in inadequate dental care. /5/ The Commission found that the documents cited by IFD were not binding interpretations of state law (Pet. App. 102a-103a). Indeed, the administration law judge (ALJ) noted in a related context that the "unofficial advisory letter" from the Deputy Attorney General of Indiana (see Resp. Br. 4-5) contained a disclaimer stating that "'the views expressed herein are those of the writer and are not to be considered to be the opinion of the Attorney General of Indiana nor a precedent of the Attorney General's office'" (Pet. App. 252a-253a (footnote omitted)). The Commission noted that no enforcement action ever had been brought by the State of Indiana against insurers that used x-rays for claims review, and that the relevant legal authority weighed against IFD's contention that insurers' use of lay personnel to grant (but not deny) insurance claims constituted the unlicensed practice of dentistry (id. at 100a-101a). To the extent that IFD's argument is an effort to resurrect its rejected state action defense (see FTC Br. 43 n.35), the documents upon which it relies do not evidence the requisite state policy to supplant competition with regulation. No Indiana regulation governs insurers' review of dental x-rays for purposes of benefits determinations and state officials did not actively supervise the private boycott conducted by IFD. See, e.g., California Retail Liquor Dealers Ass'n v. Midcal Aluminum, Inc., 445 U.S. 97, 105-106 (1980). /6/ IFD argues (Br. 23-25) that, should the Court address the manner in which noneconomic justifications are considered under the antitrust laws, it should adopt the test set forth in Wilk v. AMA, 719 F.2d 207 (7th Cir. 1983), cert. denied, Nos. 83-1455 & 83-1602 (May 21, 1984). Wilk holds that professionals may engage in exclusionary practices directed against competitors when the restraint is motivated principally by an objectively reasonable and genuinely held concern for proper scientific method that could not have been satisfied in a manner less restrictive of competition (719 F.2d at 227). To the extent Wilk indicates that a noneconomic intent or motive may outweigh a showing of anticompetitive effect, it violates this Court's teaching that antitrust analysis "focuses directly on the challenged restraint's impact on competitive conditions." National Society of Professional Engineers v. United States, 435 U.S. 679, 688 (1978). The appropriate analysis cannot credit bald assertions or unreasonable assumptions that competition is somehow harmful, and it cannot ignore a restraint's anticompetitive effect. Instead, once an agreement has been shown to have an anticompetitive effect, the inquiry should be whether the agreement in fact has counterbalancing procompetitive effects or otherwise promotes economic efficiency. For example, voluntary standards -- which are common in the health care industry -- frequently might satisfy this test in that they may promote quality without eliminating consumer choice. See FTC Br. 38 n.30. Jefferson Parish Hospital District No. 2 v. Hyde, 466 U.S. 2 (1984), is not to the contrary. The Court held in that case that a tying arrangement subject to rule of reason analysis will be invalidated only upon proof that "the actual effect" of the tie is to restrain competition unreasonably (id. at 29). The case thus addresses the showing that a plaintiff must make in order to provide its case. Contrary to the assertion of some of the amici (PSAM Br. 9-10; ACR Br. 9), Justice O'Connor's concurring opinion in that case does not suggest that a restraint is permissible if alleged health care benefits unrelated to competition outweigh its costs. Rather, consistent with the Court's opinion in Professional Engineers, the concurrence urges that "(t)he time has * * * come to abandon the 'per se' label and refocus the inquiry on the adverse economic effects, and the potential economic benefits, that (a challenged restraint) may have" (466 U.S. at 35 (emphasis added)), and notes that "(t)he ultimate decision whether a tie-in is illegal under the antitrust laws should depend upon the demonstrated economic effects of the challenged agreement" (id. at 41 (emphasis added)). In any event, the Wilk test is not satisfied here. As we have discussed, IFD's alleged concern for patient care was far from objectively reasonable, and was motivated in substantial part by a desire to shield dentists' incomes from insurers' cost containment programs. See also FTC Br. 39-43. /7/ See L. Sullivan, Handbook of the Law of Antitrust 196 (1977) (the per se rule is a "special case of rule of reason analysis"); R. Bork, The Antitrust Paradox 18 (1978); Gerhart, The Supreme Court and Antitrust Analysis: The (Near) Triumph of the Chicago School, 1982 Sup. Ct. Rev. 319, 329-330; Rahl, Price Competition and the Price Fixing Rule -- Preface and Perspective, 57 N.W. L. Rev. 137, 139-140 (1962). The Court's use of the term "unreasonable" with reference to per se rules also supports this view. See, e.g., United States v. Trenton Potteries Co., 273 U.S. 392, 397 (1927) (noting that some restraints are "themselves unreasonable and unlawful restraints without the necessity of minute inquiry"); United States v. Socony -- Vacuum Oil Co., 310 U.S. 150, 218 (1940) (describing price agreement as an unreasonable restraint of trade). /8/ Invocation of a per se rule represents a finding that a practice may be summarily condemned because it is likely to have "predominantly anticompetitive consequences," i.e., the conduct poses a clear threat to competi on and there are "generally" no "plausible" procompetitive justifications that require further scrutiny. Northwest Wholesale Stationers, Inc. v. Pacific Stationery & Printing Co. No. 83-1368 (June 11, 1985), slip op. 10. Naked price-fixing is the most notable example. See Arizona v. Maricopa County Medical Society, 457 U.S. 332, 351 (1982); United States v. Socony -- Vacuum Oil Co., 310 U.S. 150, 212-214 (1940). A determination that a per se rule should not be applied, and that a restraint should be analyzed under the rule of reason, is appropriate where the competitive threat is not clear or arguable procompetitive benefits might justify the restraint and require additional scrutiny. The subsequent inquiry under the rule of reason may be elaborate or relatively simple, depending on the evidence of the restraint's anticompetitive effects and potential benefits. This Court's decision in NCAA v. Board of Regents, supra, demonstrates that a rule of reason inquiry need not be elaborately detailed if initial investigation reveals that the practice poses a threat to competition and is not supported by a valid procompetitive justification. However, if there exist genuine procompetitive benefits to weigh against the threat to competition, the competitive effect of the restraint generally cannot be ascertained without a more detailed inquiry. /9/ This Court has required only that "(t)he agency must articulate a 'rational connection between the facts found and the choice made' * * * While (the Court) may not supply a reasoned basis for the agency's action that the agency itself has not given * * * (it) will uphold a decision of less than ideal clarity if the agency's path may reasonably be discerned." Bowman Transportation Inc. v. Arkansas-Best Freight System, Inc., 419 U.S. 281, 285-286 (1974) (citations omitted). /10/ IFD and the AMA also argue that any analogy to Professional Engineers is inappropriate because the Commission declined to find that the conspiracy denied patients information that might have led them to switch dentists (IFD Br. 22; AMA Br. 29-30). However, the portion of the Commission's opinion upon which IFD and the AMA rely (Pet. App. 89a n.14) addressed a minor argument raised by the Commission's complaint counsel, that by depriving insurers of x-rays, the conspiracy denied consumers insurer feedback about the reasonableness of dental charges that might lead consumers to switch dentists (see Complaint Counsel's Brief to the Commission 26). The Commission's refusal to elevate this tertiary argument of complaint counsel to an independent basis for condemning the conspiracy is in no way inconsistent with its other findings regarding the effects of IFD's information restraint upon competition among dentists. Thus, the Commission specifically found (Pet. App. 85a) that the refusal to provide x-rays "reduc(ed) or eliminat(ed) competition among dentists as to their policy of dealing with third-party payers" and "thwart(ed) the efforts of individual insurance companies to contain costs by offering coverage for only the least expensive adequate course of treatment" (id. at 83a). It concluded that "(t)he final victim in this distortion of the market was the patient policyholder who lost the value of his insurance company's efforts to contain costs" (id. at 86a). The AMA also argues (Br. 29) that our reliance on Paramount Famous Lasky is misplaced because the insurer cannot be equated with the buyer of dentists' services. However, as we discussed in our opening brief (at 24-26), the Commission found that "(t)he insurers broadly represent the economic interests of the dentists' patients" (Pet. App. 228a). The present situation therefore cannot meaningfully be distinguished from the conspiracy to dictate terms to purchasers held to be unlawful in Paramount Famous Lasky. /11/ Compare FTC Br. 5-6 with IFD Br. 6 & n.6. Moreover, contrary to the suggestion of the AMA (Br. 22), the Commission did find that the conspirators used coercion to enforce adherence to the conspiracy. During the IDA phase of the boycott the threat of censure was invoked and dentists reported they did not submit x-rays to insurers because they were fearful of retaliation (see Pet. App, 83a, 179a). And as the Commission noted, an express purpose of IFD was to intensify this sort of pressure. IFD's by-laws contemplated discipline of IFD members by censure, fines, suspension, or expulsion for "any action detrimental to the welfare of the organization" (id. at 217a; J.A. 62-63), and IFD's Executive Committee considered the circumstances under which IFD would seek (although "only as a last resort") to "discipline, or (undertake) acts of reprisal against non-member dentists and dissident members" (Pet. App. 220a; J.A. 120). /12/ See FTC Br. 6. IFD's brief is silent on this point. /13/ Compare FTC Br. 6-7 with IFD Br. 7. /14/ Compare FTC Br. 5 with IFD Br. 27. /15/ Compare FTC Br. 8 with IFD Br. 7-8, 11. /16/ Compare FTC Br. 9, 32 & n.24 with IFD Br. 31. /17/ Compare FTC Br. 8, 11-12 with IFD Br. 11. /18/ The AMA complains (Br. 23) that the documentary evidence discussed in our opening brief was not identified in the Commission's opinion. Of course, the reason that some of the record evidence cited in our brief was not discussed in the Commission's opinion is that the proposition for which these documents are cited was conceded by IFD in its briefs before the Commission (see FTC Br. 28). No principle of administrative law requires an agency to cite repetitive documentary evidence to support a self-evident proposition that is unchallenged by any of the parties to an administrative proceeding. /19/ This evidence alone resolves any question regarding the existence of market power. It is a settled principle of antitrust law, noted by the Commission in its opinion (Pet. App. 78a n.11) and not disputed by IFD or the court of appeals, that persons joining a preexisting antitrust conspiracy with knowledge of the prior unlawful conduct and with the intent to pursue the same unlawful objective are civilly liable for all conduct in furtherance of the conspiracy, including the acts that occurred before they joined the conspiracy. Hays v. United Fireworks Manufacturing Co., 420 F.2d 836, 844 (9th Cir. 1969); Dextone v. Building Trades Council, 60 F.2d 47, 48 (2d Cir. 1932); In re Nissan Motor Corp. Antitrust Litigation, 430 F. Supp. 231, 232-234 (S.D. Fla. 1977); Walder v. Paramount Publix Corp., 132 F. Supp. 912, 920 (S.D.N.Y. 1955), aff'd, 272 F.2d 349 (2d Cir. 1959), cert. denied, 362 U.S. 952 (1960). Applying this principle, the Commission properly concluded that IFD could be charged with a restraint of trade in a statewide market on the basis of IDA's overwhelming statewide market power; indeed, the express purpose of the formation of IFD was to perpetuate the IDA conspiracy. Pet. App. 85a n.12. A contrary view would mean that even though the Commission could stop the statewide conspirator (IDA) from continuing its unlawful conduct -- as the Commission did by means of a consent agreement (Pet. App. 60a n.2) -- it would be unable to act against groups organized to continue the conspiracy until such time as those groups regenerated the original restraint of trade on a scale comparable to its original broad scale. /20/ IFD also asserts that, in any event, "a consumer has no interest in the preservation of a fixed number of competitors greater than the number required to assure his being able to buy at a competitive price" (Br. 33). But this is simply another way of stating the requirement that a restraint must unreasonably restrict competition. The evidence in the record shows that this requirement is satisfied here, where the conspirators achieved widespread adherence to their agreement. IFD cannot seriously contend that its conspiracy is not unlawful because "new dentists * * * would enter the market and any existing anticompetitive effect would be short-lived" or because a few dentists already in the market might decline to join the conspiracy (Br. 33-34). That rationale would equally suggest abandonment of the per se rule against price-fixing (and compel exhaustive analysis of similar horizontal conspiracies that now may be condemned in more abbreviated fashion) on the ground that any such conspiracy could theoretically be undercut by new entrants or existing market participants who decline to participate.