In the United States v. Ewell et al., 1965, the Supreme Court ruled on a case involving narcotics offenses and subsequent prosecution for tax evasion related to those same drugs. The defendants argued that this constituted double jeopardy - being tried twice for the same crime - which is prohibited by the Fifth Amendment of the U.S. Constitution. However, in its decision, the Supreme Court held that each charge required proof of a fact not necessary in proving other charges; therefore, they were separate offenses under Blockburger's test (a legal standard used to determine whether two charged crimes are sufficiently different so as not to violate double jeopardy rights). Furthermore, it was found that there was no unnecessary delay between indictments or any attempt by government prosecutors to gain an unfair advantage over defendants through manipulation of their prosecutions' timing.

In the dissenting opinion for United States v. Ewell, Justice Douglas argued that the majority's decision violated the defendants' right to a speedy trial as guaranteed by the Sixth Amendment. He contended that this right should not be compromised even in cases where there is no prejudice against the defendant due to delay. The government had waited nearly three years after their initial indictment on tax evasion charges before bringing narcotics charges based on evidence already available at first indictment time. Douglas believed such delays could potentially allow prosecutors an unfair advantage by giving them more time to build their case while leaving defendants in prolonged legal uncertainty and anxiety about potential punishment, which he saw as contrary to principles of justice and fair play.