In Screws v. United States, 325 U.S. 91 (1945), the Court upheld a statute under which several law enforcement officers had been convicted of illegally depriving a prisoner of his life without "due process" of law. See 325 U.S. at 93, 100, 65 S. Ct. 1031. The defendants were prosecuted under 18 U.S.C. 20, FN12 which made it illegal to " 'willfully' " deprive another " 'of any rights, privileges, or immunities secured or protected by the Constitution and laws of the United States' " under the color of state law. See id. They argued to the Court that this provision was impermissibly vague as applied to their convictions for depriving the deceased of "due process" because the law provided "no ascertainable standard of guilt." See 325 U.S. at 94-95, 65 S. Ct. 1031. Justice Douglas, writing for a four-justice plurality, said that: FN12. 18 U.S.C. 20 was the predecessor to 18 U.S.C. 242, discussed infra. the decisions of the courts are, to be sure, a source of reference for ascertaining the specific content of the concept of due process. But even so the Act would incorporate by reference a large body of changing and uncertain law. That law is not always reducible to specific rules, is expressible only in general terms, and turns many times on the facts of a particular case. Accordingly, it is argued that such a body of legal principles lacks the basic specificity necessary for criminal statutes under our system of government. Congress did not define what it desired to punish but referred the citizen to a comprehensive law library in order to ascertain what acts were prohibited. To enforce such a statute would be like sanctioning the practice of Caligula who "published the law, but it was written in a very small hand, and posted up in a corner, so that no one could make a copy of it." (325 U.S. at 96, 65 S. Ct. 1031.) Indeed, seven justices indicated that 20's use of "due process" to define criminal conduct would have been unconstitutionally vague without something else to mitigate its ambiguous incorporation of constitutional principles. See id. at 105, 65 S. Ct. 1031 ( 20 must be construed with narrow scienter requirement to "avoid grave constitutional questions"); 325 U.S. at 149-150, 65 S. Ct. 1031 (Roberts, J., dissenting) ("all but two" justices agreed on this issue). However, the plurality concluded that the statute could be saved by construing "willfully" to require a specific intent to purposefully deprive another of a specific federal right made definite by the express terms of the Constitution and laws of the United States or by the decisions interpreting them. See 325 U.S. at 100-105, 65 S. Ct. 1031. Thus, Screws recognized that the expansive language of due process that provides a basis for judicial review is, when incorporated by reference into 242, generally ill-suited to the far different task of giving fair warning about the scope of criminal liability.