For decades, online sports betting has been illegal in the US outside Nevada. With a Supreme Court ruling Monday, that’s about to change, likely before the upcoming NFL season kicks off. But don’t get too excited—or horrified, depending on your perspective—about the future of online sports gambling just yet; it won’t come all at once, and it won’t be everywhere.

In a 6–3 ruling, the Supreme Court backed the state of New Jersey’s challenge to the Professional and Amateur Sports Protection Act, a 1992 law that banned states other than Nevada from operating a sports book. The decision doesn’t legalize gambling nationwide, but it allows states to pass their own laws to that effect.

The upshot: Sports betting, once relegated to Nevada casino corners and black-market online bookies, is about to go mainstream in a big way. While there’s no official accounting of the size of the illicit sports betting market in the US, experts estimate total wagers at anywhere from $80 billion to $150 billion annually.

Gambling Compliance, a company that provides legal and regulatory services to casinos, pegs the potential revenue to casinos from legalized US sports betting at anywhere between $2 billion and $5.8 billion per year, with states taking a still-to-be-determined cut.

Read more about the future of online sports betting at Wired