Rule 33's deadline is a nonjurisdictional claim-processing rule. A properly raised timeliness objection must be enforced, but the objection can be forfeited.
Procedural disposition
The Court reversed the Seventh Circuit because the government waited too long to assert untimeliness.
Material limitations
The case construed an older Rule 33 and Rule 45. The present filing periods and the current Rule 45 extension language must come from the current rules, not from the historical numerical deadlines recited in the opinion.