The court may order that separate cases be tried together as though brought in a single indictment or information if all offenses and all defendants could have been joined in a single indictment or information.
Notes of Advisory Committee on Rules—1944
This rule is substantially a restatement of existing law, 18 U.S.C. [former] 557 (Indictments and presentments; joinder of charges); Logan v. United States, 144 U.S. 263, 296; Showalter v. United States, 260 F. 719 (C.C.A. 4th)—cert. den., 250 U.S. 672; Hostetter v. United States, 16 F.2d 921 (C.C.A. 8th); Capone v. United States, 51 F.2d 609, 619–620 (C.C.A. 7th).
Committee Notes on Rules—2002 Amendment
The language of Rule 13 has been amended as part of the general restyling of the Criminal Rules to make them more easily understood and to make style and terminology consistent throughout the rules. These changes are intended to be stylistic only.