John Marshall Harlan II,
Swift Company v. Wickham — Opinion of the Court
“ For a simple provision prohibiting the restraint of the enforcement of any state statute except by a three-judge court would manifestly have sufficed to embrace every such suit whatever its particular constitutional ground. It is thus quite permissible to read the phrase in question as one of limitation, signifying a congressional purpose to confine the three-judge court requirement to injunction suits depending directly upon a substantive provision of the Constitution, leaving cases of conflict with a federal statute (or treaty) to follow their normal course in a single-judge court. ”
