DES MOINES — A pending decision by the U.S. Supreme Court could open the door to legalized sports gambling in any state that approves it.

A nonprofit organization that supports Iowa casinos plans to draft legislation that would legalize sports gambling in the state, should the U.S. Supreme Court rule in a way that makes that possible.

“I think there’s a great deal of interest among people (who want) the opportunity to bet on a game and do it in a regulated environment,” said Wes Ehrecke, president and CEO of the Iowa Gaming Association. “... I think a lot of people have a great deal of interest in sports and betting on sports.”

Americans illegally wager $150 billion on U.S. sports annually. Of the $4.7 billion wagered on last season’s Super Bowl, 97 percent was illegal, according to estimates from the American Gaming Association, which supports legalized sports betting.

Only four states — Nevada, Montana, Delaware and Oregon — are allowed to facilitate sports gambling under a 1992 federal law.

That law has been challenged by New Jersey in a case heard Monday by the U.S. Supreme Court.

Should the court rule in favor of New Jersey, all states would be free to legalize sports gambling.

The Iowa Gaming Association wants to be prepared for that possibility. Ehrecke said his organization plans to draft a bill that would legalize sports gambling in Iowa if the U.S. Supreme Court makes that possible, and hopes that bill is introduced during the upcoming legislative session.

If the high court doesn’t rule before the session ends, Ehrecke said, lawmakers could approve a bill that legalizes sports gambling contingent on a favorable ruling. Such a bill would legalize sports betting at casinos, regulated by the state gaming commission.

Iowa would legalize sports gambling within five years of a favorable Supreme Court, according to a report from the California research firm Eilers & Krejcik Gaming, The Associated Press reported. A total of 32 states would legalize sports wagering within five years, the research firm’s report said.

Legalized sports wagering could provide a financial boon to casinos and the state. Although state estimates are not available, Eilers & Krejcik estimates a legal sports gambling market would be worth more than $6 billion, the AP reported.

“It’s going to generate revenue for the state as well,” Ehrecke said. “That would go to more worthwhile causes, like our gaming revenue, and tax revenue, does now.”

Opposing New Jersey in the high court case are the professional sports leagues and the NCAA, which believe nationwide legal sports gambling would hurt the integrity of their games.

A key state lawmaker said he is taking a wait-and-see approach.

“I don’t want to get ahead of ourselves here. Once we find out what the Supreme Court says, then we really need to assess what the people of Iowa want. Do they want sports betting or not?” said Ken Rizer, a state lawmaker from Marion who chairs the House State Government Committee, through which any gambling bill would have to pass.

At the heart of the Supreme Court case is the question of the 10th Amendment to the U.S. Constitution, to what extent the federal government can force laws upon the states.

The court’s decision could have repercussions beyond sports gambling.

“(The ruling) could have repercussions in areas that go well beyond sports betting: gun control, immigration, sanctuary cities,” Daniel Wallach, a Fort Lauderdale lawyer who specializes in gaming and sports law, told the Washington Post. “It is the most important federalism case the Supreme Court has heard in many, many years.”

New Jersey has lost at every stage of its legal journey, but experts believe some of the Supreme Court justices’ questions during Monday’s hearing suggest the high court will rule in favor of the states.