People make bets in the sports book at the South Point hotel and casino in Las Vegas on Monday. Could Maryland, the District or Virginia follow suit? (John Locher/AP)

Legalized sports betting could come to the nation’s capital or its surroundings after a Supreme Court ruling this week opened the way for states to allow it. But where, and how fast, remain very much up in the air.

Nearly 20 states have introduced bills to legalize sports betting or allow voters to decide. The District and Virginia aren’t among them.

In Maryland, a bill calling for a voter referendum on the issue passed the House of Delegates this year, but not the Senate. Any betting proposal now must wait until next year, barring a special legislative session, which the office of Gov. Larry Hogan (R) said he has no plans to initiate. That pushes the soonest potential legalization to 2020.

“The governor has previously expressed support for the rights of states to make this determination,” Hogan spokeswoman Shareese Churchill said in an email. “We anticipate this issue will be debated in the next legislative session.”

Del. Jason C. Buckel (R-Allegany), who has sponsored past sports betting legislation, said the bill’s failure could put Maryland at a competitive disadvantage. “It’s a shame that all our neighboring states and competing casinos are going to be up and running with this new amenity for their customers,” he said.

Indeed, in the District, one council member said he’d like to get betting in place before Maryland and Virginia do, so gamblers from across the region can spend their dollars in Washington.

“This is a source of enormous revenue, and we need to move forward as quickly as possible,” said council member Jack Evans (D-Ward 2), who’s planning to introduce a bill.

But first, Evans — who was a driving force behind bringing Major League Baseball back to Washington and building the publicly financed Nats Park — said he’s trying to sort out questions, such as where revenue from sports bets should go.

“Gambling has always been a mixed bag in the District. When we looked at casino gambling, there was a lot of opposition to it, particularly from churches,” ­Evans said. “I personally want to make this happen, but it’s a long road.”

Virginia, unlike Maryland, has so far resisted any form of casino gambling. Its conservative legislature turned away riverboat gambling in the 1990s, outlawed Internet gambling cafes in the 2000s and has kept a casino bill bottled up in a Senate committee for the past five years.

But momentum for gambling in the commonwealth is getting a push from the popularity of the MGM National Harbor casino just across the Potomac River in Maryland, which estimates that at least 40 percent of its business comes from Virginia.

During the first four months of this year, Maryland’s six casinos hauled in more than $414 million, with nearly $150 million of that going to state and local coffers.

Virginia Gov. Ralph Northam (D) has taken note and said it may be time for something similar in his state. On sports betting, his office was noncommittal this week. “We are still reviewing the ruling and should the General Assembly take up legislation on this issue, we’d review that as well,” Northam spokeswoman Ofirah Yheskel said in an email.

The Supreme Court struck down a federal law that kept most states from authorizing sports betting, ruling in favor of New Jersey, which had challenged the statute.

That state has been preparing for legalized sports wagering since 2012, and many locations are ready to move quickly. Monmouth Park, a racetrack on the Jersey Shore, says it could open betting windows within the next two weeks. Delaware could also have betting windows open soon, and other states are poised to follow. A 2017 report from Eilers & Krejcik Gaming estimated that as many as 32 states could offer legal sports betting within five years.

Experts suggest that illegal sports betting in the United States is a $50 billion to $150 billion business, though it’s probably impossible to accurately estimate. According to research by UNLV’s Center for Gaming Research, legal sports betting in Nevada totaled nearly $5 billion last year, led by wagers on football — both college and professional — which accounted for $1.76 billion.

Many in the gambling and sports industries in the D.C. region have greeted the Supreme Court’s ruling enthusiastically.

“The Court’s decision is both a victory for state’s rights and for the millions of Americans who want to legally bet on sports in a safe, regulated environment,” Joe Weinberg, managing partner of Maryland casino developer Cordish Companies, said in a statement. “Sports betting should be made available exclusively through the regulated casinos in Maryland, where it is best positioned to protect consumers and maximize tax revenues to the state.”

Washington Wizards, Capitals and Mystics owner Ted Leonsis also said he’s eager to embrace legalized betting, though he said there are “a huge number of questions” about how the court’s decision will play out.

“Many ask if this decision will impact the integrity of sports themselves,” Leonsis said in a statement. “I think it’s just the opposite. I think that the increased transparency that will accompany more legalized betting around the country will only further protect against potential corruption.”

Fenit Nirappil, Greg Schneider and Luz Lazo contributed to this report.