What Types of Gambling Are Legal?
When it comes to what gambling activities are legal and the extent and scope of the legal gambling activity, state gambling regulators rule! Gambling operations – licensing, regulation, and enforcement--are overseen at the state level. While there some federal laws, like the Wire Act or the Unlawful Internet Gambling Enforcement Act (UIGEA) which affect gambling, the vast majority of gambling regulation in the United States is conducted by the states.
The line between what kinds of gambling activity are legal or illegal varies widely from state to state, as does the forms of gambling permitted within the state’s local jurisdictions. (An overview of the forms of gambling by state can be found here.) What one state legalizes, another specifically prohibits (or restricts). For example: some states ban online gambling and sports betting entirely, while others permit some forms of betting and waging.
States that allow some form of gambling, via a gaming commission or other regulatory authority, enforce rules for:
(2) social gaming
Regarding (1) and (2), generally, there are tightly defined exceptions for charitable or social gambling, making gambling legal which would otherwise not be. Otherwise, apart from limited charitable and social gambling, the only legal gambling is with a gambling operator or provider (a card room, a casino, a sports wagering venue, or website) licensed by the state, or with an Indian tribe itself authorized to offer gambling. Any gambling, regardless of its form, offered by someone not authorized by a state to offer gambling services within it is illegal.
But it's also not enough to know that the provider is licensed and legal. The games they offer must also be legal. States will lay out in often-excruciating detail what forms of games are legal, and even the permitted rules for those games. For example, New Jersey has approximately thirty (30) pages of its Administrative Code devoted solely to the rules for one variation or subset of poker (double-draw poker).
So if a game is not specifically authorized as legal, or the variation or way it is being played is not legal, then it is illegal gambling even if offered by an otherwise-licensed and-legal provider.
Gambling oversight and enforcement
Fortunately, it is not necessary for gamblers to review the rules for each game and compare it to how the game is run in a casino or on an online website to make sure that they are not violating the law by playing.
States focus their enforcement efforts on gambling operators or providers. Someone playing in good faith at a location that any reasonable person would believe is licensed to legally offer gambling will not be liable because a game turns out to not be authorized or is being offered in a way that violates state regulations. The provider/gaming establishment, not the individual players, will be held liable for offering an unauthorized game. (This protection from criminal liability does depend on it being reasonable for the player to believe that the location or website may legally offer gambling. If the location, for example, is a website that was plainly or obviously illegal, then in many states, the player could face liability or penalties.)