In the 1916 case Caminetti v. United States, the U.S. Supreme Court was tasked with interpreting the White Slave Traffic Act of 1910, also known as the Mann Act. The defendants, F. Drew Caminetti and Maury I. Diggs were convicted for transporting women across state lines for "immoral purposes." They argued that their actions did not violate this law because it only applied to commercialized vice or prostitution and they had no intent to profit from these acts - they merely transported their mistresses for private consensual sexual activity. The court rejected this argument in a 7-2 decision upholding their convictions stating that Congress intended broader application of the act beyond just instances involving commerce or trade in vice; it aimed at suppressing all forms of immoral practices which could result from such interstate transportation regardless if there's an element of commerce involved or not. This interpretation expanded federal power over individual conduct under its constitutional authority to regulate interstate commerce and set precedent on how broadly laws can be interpreted when moral issues are concerned.

In the dissenting opinion for Caminetti v. United States, Justice McKenna expressed concern over the majority's broad interpretation of the White Slave Traffic Act (also known as Mann Act). He argued that this expansive reading extended beyond what Congress intended when it passed legislation to combat forced prostitution and other forms of sexual slavery. According to Justice McKenna, by applying the law to consensual extramarital affairs, as in Mr. Caminetti's case who transported a woman across state lines for an affair, was not within its original purpose or scope. The justice contended that such application could potentially criminalize any immoral act involving women crossing state borders which would be an unwarranted extension of federal power into areas traditionally regulated by states' police powers.