Enforcement of federal gambling laws has met with some controversy. Challenges to gambling laws have been based on the Commerce Clause, First Amendment guarantee of free speech, and Due Process Clause. The Commerce Clause concerns are somewhat satisfied by the commercial nature of the gambling business. Free speech objections are also weakened by the limited First Amendment protection of crimes facilitating speech. And due process arguments suffer when financial transactions take place within the United States.

While gambling laws are largely state-based, federal law is often invoked when the activities are facilitated over the internet. Under 31 U.S.C. 5362(10), online gambling involves placing, receiving, or transmitting bets using at least a portion of the internet. However, state gambling laws may vary from state to state.