Rule 8(b) states that '[t]wo or more defendants may be charged in the same indictment or information if they are alleged to have participated in the same act or transaction or in the same series of acts or transactions constituting an offense or offenses.' There is a preference in the federal system for joint trials of defendants who are indicted together. Joint trials 'play a vital role in the criminal justice system.' Richardson v. Marsh, 481 U. S. 200, 209 (1987). They promote efficiency and 'serve the interests of justice by avoiding the scandal and inequity of inconsistent verdicts.' Id., at 210. For these reasons, courts repeatedly have approved of joint trials. See ibid.; Opper v. United States, 348 U. S. 84, 95 (1954); United States v. Marchant, 12 Wheat. 480 (1827); cf. 1 C. Wright, Federal Practice and Procedure § 223 (2d ed. 1982) (citing lower court opinions to the same effect).
In Schaffer v. United States, 362 U.S. 511, 80 S. Ct. 945, 4 L. Ed. 2d 921 (1960), the Supreme Court held that the propriety of joinder under Rule 8(b) is to be judged according to the language of the ...