Most estimates are in the hundreds of billions of dollars, but no one knows for sure how much money Americans bet on sports every year. Whatever the amount, it's enough to fuel the massive offshore bookmaking industry that consists of hundreds of online sportsbooks. It's also large enough to get the attention of cash-strapped states and ratings-dependent sports leagues that now seem more accepting of betting.
The American Gaming Association estimates $150 billion is bet annually on sports by Americans. Professional gamblers say that's too high. Professional bookmakers say it's too low. The $150 billion mark must be a good line.
"I would bet over $150 billion before I would bet under," veteran offshore sportsbook operator Scott Kaminsky of TheGreek.com wrote in an email to ESPN.
On Monday, the U.S. Supreme Court will hear a case that will not only shape the future of American sports betting, but also begin to divvy up a market that experts say could be worth as much as $5.8 billion in annual revenue. The case is centered on the federal ban on legal sports betting, the Professional and Amateur Sports Protection Act of 1992 (PASPA) and pits New Jersey Gov. Chris Christie against the NCAA, NFL, NBA, NHL and Major League Baseball. Former U.S. Solicitor General Ted Olson will represent New Jersey, while Paul Clement will argue for the sports leagues.
Oral arguments run from 10 to 11 a.m. ET on Monday. A decision is anticipated by the end of June.
Here is what you need to know going into the case.
Potential outcomes
The Supreme Court could completely strike down the federal ban on sports betting (PASPA), opening it up to states to make the decision on whether to offer it and how to regulate it.
The Supreme Court could uphold the federal ban (PASPA) but rule that New Jersey's 2014 law, which repealed many of the state's prohibitions on sports betting, complies with PASPA. This would leave New Jersey, for the time being, with a pseudo-East Coast monopoly on single-game sports betting.
The Supreme Court could affirm the constitutionality of the federal ban, maintaining the status quo. "I don't think they would take the case if they were just going to affirm PASPA," said Marc Dunbar, a Florida attorney with Jones Walker LLP who has followed the case closely.
The above scenarios are the most common predictions, but many legal experts, including Dunbar, expect a narrow, nuanced ruling.
Where do the sports leagues stand?
Dozens of states, the professional sports leagues, international gaming companies and members of Congress are not waiting around for the Supreme Court to rule. Instead, they are taking steps to get out in front of the decision and be prepared for a variety of outcomes.
NBA
The NBA has taken a leadership role on the issue. Commissioner Adam Silver jump-started the conversation with an op-ed in The New York Times in November 2014. Silver called on Congress to create a federal framework and allow states a choice of whether to offer legal sports betting.
The NBA remains a plaintiff in the case against New Jersey because it prefers a federal solution to regulating sports betting over a state-by-state approach.
Dan Spillane, senior vice president and assistant general counsel for the NBA, said at a November gaming conference in Washington hosted by Sportradar that the league has been discussing potential avenues with advisers in D.C. and working on a draft of a potential federal framework. The NBA believes that any federal framework should include an opt-out option for any sports leagues or states that may not want sports betting, in addition to basic integrity measures like information-sharing protocols and consumer protections.
"A federal framework is easier, and that's the opportunity right now, to put a federal framework in place before everything starts to work out in a piecemeal way," Spillane said at Sportradar's "Future of Sports Gambling in the U.S." conference in November at the Russell Senate Office Building. "We haven't been knocking on doors in this building on this, but we are working with people here in town, making sure we're ready to participate in the discussions when they start to get serious."
NFL
The NFL has strongly opposed the expansion of legal sports betting for decades over concerns it would threaten the integrity of the games. However, commissioner Roger Goodell has acknowledged that Nevada's regulatory oversight could be beneficial in regard to the Oakland Raiders' relocation to Las Vegas. The Raiders are expected to arrive in Sin City by 2020.
The NFL did not return multiple emails inquiring about the league's current position on expanding legal sports betting.
MLB
Major League Baseball has begun to align itself with the NBA's position, with commissioner Rob Manfred initially saying that the issue of legalizing sports betting needs fresh consideration.
"If there's going to be a change in the regulatory structure with respects to sports gambling, we need to be in a position to meaningfully engage and shape, try to shape, what the new regulatory scheme looks like," Manfred told the Baseball Writers' Association of America in July. "We're in the process of talking to our owners and figuring out where we want to be in the event that there is in fact a significant change coming."
In late September, executives for Major League Baseball were in Las Vegas to meet with sportsbook operators to learn how the industry works.
NHL
The NHL is also becoming more comfortable with regulated sports betting, electing this summer to not request a prohibition on betting on its new Nevada franchise, the Vegas Golden Knights. The mobile sports betting apps offered by the majority of Nevada sportsbooks are accessible inside T-Mobile Arena, where the Golden Knights play their home games.
At the same time, the NHL remains a plaintiff against New Jersey and has repeatedly decried the irreparable harm that the league would suffer if legal sports betting were to expand.
"[N]ew Jersey's contemplated sports betting scheme threatens serious and irreparable harm to the NHL, harm that cannot be remedied or compensated for by any amount on monetary damages," NHL commissioner Gary Bettman wrote in a legal filing in the case on Aug. 9, 2012.
NCAA
The NCAA is not actively working on the issue in Washington, according to a spokesperson. The Division I Athletic Directors Association, however, did hold a panel on sports betting at its annual meeting in late September in an effort to educate its members on an issue that is still widely seen as a taboo in college sports.
Multiple sources connected to the case said all of the professional sports leagues are educating themselves on the issues surrounding legal betting and preparing contingency plans should the Supreme Court strike down PASPA.
The professional sports leagues have partnered with European sports data companies that provide odds and information to sportsbooks around the world. The NBA, which now openly supports expanding legal sports betting with a federal framework, has worked with Las Vegas-based consultants for decades, and even the NFL has hired services to monitor for unusual betting patterns in the past.
"People are kidding themselves if they think that [the leagues] have any motivation other than money," gaming attorney Kate C. Lowenhar-Fisher said in a recent phone interview. "There's none."
Potential decision days
The Supreme Court does not reveal the dates when decisions on individual cases will be released, but it does set a number of dates throughout the term when rulings will be announced. Legal experts believe that later in the calendar is more likely than earlier for the release of the sports betting decision. Potential decision dates include:
Dec. 11;
Jan. 22;
March 5;
April 2 and 30;
May 14, 21 and 29;
June 4, 11, 18 and 29.
Regardless of the Supreme Court's ruling, a push to compel Congress to act on sports betting is expected to follow. In some cases, it has already begun, and with bipartisan support.
Rep. Frank Pallone Jr., Democrat of New Jersey and the ranking member on the House Energy and Commerce Committee, has released draft legislation, the GAME Act, which aims to repeal PASPA and harmonize the nation's gambling laws.
Republican congressmen Doug Collins of Georgia and Matt Gaetz of Florida also have called for hearings on PASPA. "The fight to legalize sports betting is bipartisan," Rep. Josh Gotteheimer, a New Jersey Democrat, said in November. "Let's get this done."
"This is not a matter of timing. This is not a matter of when this will happen," added Washington Wizards owner Ted Leonsis. "There is an inevitability here that we will move forward with gambling being part of the overall sports landscape."