The enactment of federal laws governing online gambling has been challenged on constitutional grounds. The Commerce Clause, the First Amendment, and the Due Process Clause have been cited as arguments against such laws. Commerce Clause arguments have not been successful, perhaps because of the commercial nature of the gambling business, and First Amendment arguments have weakened when financial transactions involving the United States are involved.
While Internet gambling is a matter of state law, federal law is often used to enforce state laws. For instance, 31 U.S.C. 5362(a) defines unlawful Internet gambling as the use of an Internet service for gambling. Further, this type of gambling may not be carried out if the internet is not accessible in a particular state.