Opinion of the Court
Opinion of Gorsuch, J.
ternal quotation marks omitted and emphasis added). Notably, too, Acker cited to and relied on cases applying this same principle to penalty provisions under a wide array of statutes, including the Communications Act of 1934, a bankruptcy law, and the National Banking Act. See ibid. (citing FCC v. American Broadcasting Co., 347 U. S. 284, 296 (1954); Keppel v. Tiffin Savings Bank, 197 U. S. 356, 362 (1905); and Tiffany v. National Bank of Mo., 18 Wall. 409, 410 (1874)); see also Scalia & Garner at 297 (the rule of lenity applies “to civil penalties”).
Two additional features of this case make it a particularly appropriate candidate for the rule of lenity. First, the rule exists in part to protect the Due Process Clause’s promise that “a fair warning should be given to the world in language that the common world will understand, of what the law intends to do if a certain line is passed.” McBoyle v. United States, 283 U. S. 25, 27 (1931); see also Connally v. General Constr. Co., 269 U. S. 385, 393 (1926); Wooden v. United States, 595 U. S. ___, ___–___ (2022) (Gorsuch, J., concurring in judgment) (slip op., at 6–9). And the government’s current theory poses a serious fair-notice problem. The relevant provisions of the BSA nowhere discuss per-account penalties for nonwillful violations. A number of the government’s own public guidance documents have seemingly warned of per-report, not per-account, penalties for non-willful violations. See Part II–B, supra; Brief for Tax Counsel 6–24. We are even told that, until 2008 and 2009, when the government began aggressively enforcing FBAR penalties, “many experienced tax professionals and return preparers were not aware of the FBAR reporting obligations,” let alone aware of the government’s current theory about the scope of penalties for non-willful violations. Brief for Center for Taxpayer Rights as Amicus Curiae 24, 20–28, and n. 21. If many experienced accountants were unable to anticipate the government’s current theory, we do not see how “the common world” had fair notice of it. McBoyle, 283
