Credit for good behavior for a federal prisoner is awarded after, rather than before, the fact under 18 U. S. C. §3624(b)(1).
Of course, computation of federal sentence credit will ordinarily be a matter of indifference to the state practitioner, but the Court’s discussion of the rule of lenity may hold interest:
Fourth, petitioners ask us to invoke the rule of lenity and construe §3624 (2006 ed.) in their favor, that is, in a way that will maximize the amount of available good time credit. We may assume for present purposes that §3624(b) can be construed as imposing a criminal penalty. See Bifulco v. United States, 447 U. S. 381, 387 (1980) (rule of lenity applies to “interpretations of . . . the penalties” imposed by “criminal prohibitions”); but see Sash v. Zenk, 428 F. 3d 132, 134 (CA2 2005) (Sotomayor, J.) (holding that §3624(b) is not a criminal statute for the purposes of the rule of lenity). Even so, the rule of lenity only applies if, after considering text, structure, history, and purpose, there remains a “grievous ambiguity or uncertainty in the statute,” Muscarello v. United States, 524 U. S. 125, 139 (1998) (internal quotation marks omitted), such that the Court must simply “‘guess as to what Congress intended.’” Bifulco, supra, at 387 (quoting Ladner v. United States, 358 U. S. 169, 178 (1958)). See United States v. Hayes, 555 U. S. ___, ___ (2009) (slip op., at 13); United States v. R. L. C., 503 U. S. 291, 305–306 (1992) (plurality opinion). Having so considered the statute, we do not believe that there remains a “grievous ambiguity or uncertainty” in the statutory provision before us. Nor need we now simply “guess” what the statute means.
Grievous? Very odd term to use in this context. What about articulation of state principles? “The rule of lenity comes into play only after two conditions are met: the penal statute must be ambiguous, and we must be unable to clarify the intent of the legislature by resort to legislative history,” State v. Kevin F. McGuire, 2007 WI App 139, ¶34. Ambiguity unclarified by legislative history isn’t quite the same as “grievous” ambiguity. But that, as it turns out, is probably a mere detail, the larger point being that whatever rhetoric is employed, lenity is a rule of last resort.