In the 2004 case of David Whitfield v. United States, the Supreme Court ruled unanimously that a conviction for conspiracy to commit money laundering does not require proof that the defendant knew his conduct violated a specific provision of U.S. law. The case involved David Whitfield and Haywood Don Hall who were convicted in North Carolina for their involvement in an international telemarketing scheme which defrauded victims out of more than $6 million dollars. They appealed their convictions arguing they did not know their actions constituted money laundering under federal law, but only believed they were committing fraud. However, Justice Sandra Day O'Connor wrote on behalf of the court stating that "the Government need only prove that defendants agreed to commit an act which constitutes an offense," and it is irrelevant whether or not they knew this act was illegal.

In the dissenting opinion for David Whitfield v. United States, Justice Stevens argued that the majority's interpretation of "in relation to" in 18 U.S.C §924(c) was overly broad and inconsistent with Congress' intent. He contended that this phrase should be interpreted more narrowly to require a closer connection between the firearm possession and drug trafficking crime than merely having a gun present during criminal activity. In his view, there must be evidence showing an active employment or use of the weapon in furtherance of drug trafficking activities such as brandishing, displaying or firing it. The mere presence or proximity of a firearm is not enough to satisfy this requirement unless it plays some purposeful role in the crime itself. By interpreting "in relation to" so broadly, he believed that majority expanded federal jurisdiction over local crimes which could lead to unfair results.