Opinion of the Court
statute that says the attorney general “may institute an action for a civil penalty of $1,000” for violations of “this subtitle or a rule or order adopted by the [Texas Medical B]oard.” Tex. Occ. Code Ann. §165.101 (West 2012). But the qualification “this subtitle” limits the attorney general’s enforcement authority to the Texas Occupational Code, specifically §§151.001 through 171.024. By contrast, S. B. 8 is codified in the Texas Health and Safety Code at §§171.201–171.212. The Act thus does not fall within “this subtitle.” Nor have the petitioners identified for us any “rule or order adopted by the” Texas Medical Board related to S. B. 8 that the attorney general might enforce against them. To be sure, some of our colleagues suggest that the Board might in the future promulgate such a rule and the attorney general might then undertake an enforcement action. Post, at 3 (opinion of Roberts, C. J.) (citing 22 Tex. Admin. Code §190.8(7) (West 2021)). But this is a series of hypotheticals and an argument even the petitioners do not attempt to advance for themselves.
Even if we could overcome this problem, doing so would only expose another. Supposing the attorney general did have some enforcement authority under S. B. 8, the petitioners have identified nothing that might allow a federal court to parlay that authority, or any defendant’s enforcement authority, into an injunction against any and all unnamed private persons who might seek to bring their own S. B. 8 suits. The equitable powers of federal courts are limited by historical practice. Atlas Life Ins. Co. v. W. I. Southern, Inc., 306 U. S. 563, 568 (1939). “A court of equity is as much so limited as a court of law.” Alemite Mfg. Corp. v. Staff, 42 F. 2d 832 (CA2 1930) (L. Hand, J.). Consistent with historical practice, a federal court exercising its equitable authority may enjoin named defendants from taking specified unlawful actions. But under traditional equitable principles, no court may “lawfully enjoin the world at
