Say you’re sitting in an airport on the way to Las Vegas reading about the presidential race, and you’re so sure that Donald Trump will pull an upset that you want to put some money on it. You get to a casino, march up to a sports book window and try to put down your bet. You will be very disappointed.

Las Vegas doesn’t offer odds on the presidential election. Nor can you bet on events such as the Oscars or Brexit, despite the ubiquity of odds on those events quoted in the news and on social media.

Online and in the U.K., there’s a wild west of betting options. But in the real American West of Nevada, the books are driven by something else: restrictive, conservative regulation. And those rules, like a disgruntled online commenter, have one overriding philosophy: stick to sports.

Sportsbooks weren’t always synonymous with Las Vegas. Because of a high tax rate on sports bets, the large casinos of early Vegas ignored sports wagering, allowing smaller operators known as turf clubs to dominate the industry. It wasn’t until the early 1970s that Nevada’s U.S. Sen. Howard Cannon spearheaded an effort to reduce the onerous excise tax, prompting casinos to enter the sportsbook business.

With limited bookmaking experience available, the casinos hired former sports gamblers to staff the newly formed sportsbooks and everyone tried to figure things out in real time. Jimmy Vaccaro, a young gambler who moved to Las Vegas from Ohio in 1975, was hired by Michael Gaughan to start the sports book at the now-defunct Royal Inn. As Vaccaro told me in 2013, “Michael Gaughan called me upstairs. He said, ‘Do you know how to run a sportsbook?’ I said ‘No.’” Gaughan replied, “Good, neither do I. We will start one together.”

Back then, you could bet on almost anything. In downtown Las Vegas, Michael’s father, Jackie Gaughan, owner of the El Cortez Hotel and Casino, was looking for ways to make his sports book stand out from the crowd. In 1979, Skylab, the United States’ first space station, was about to fall back to Earth, so Gaughan decided to offer odds on where Skylab would land, including 10,000 to 1 if it landed on the El Cortez itself. Australia, a 30-to-1 bet as the landing spot, was the ultimate winner, but the Skylab bet represented more than just a single wager. It was the first of the bets that caught the country’s attention and is the forefather of the ubiquitous odds in global betting markets today, used more for publicity than profit.

A year later, Sonny Reizner, a publicity-seeking bettor who was running the sportsbook at the Castaways casino east of the El Cortez, found the perfect high-profile event on which to take bets: the TV show “Dallas.” As 25 million people watched, the season finale ended with the shooting of J.R. Ewing. Reizner offered odds on who shot J.R, and the bet quickly went national. As Reizner described in his book, “The Best of Sonny Reizner,” “Little old ladies from Iowa wanted to bet. Baptist ministers wanted to bet. Rabbis wanted to bet. Thirteen-year-old kids wanted to bet. Everybody thought they knew who shot J.R. and were willing to invest a few dollars on the outcome.”

But a lot of people involved in the TV show knew who shot J.R., so the Nevada Gaming Control Board (NGCB) decided that the bet wasn’t fair. The board forced Reizner to take it down and refund the money.

And four years later, in July of 1985, Nevada regulators codified the rules: No betting on anything other than professional athletic events on the field of play. Collegiate sports and Olympic events were added later, but the political prohibition remains clear in the regulations: no wagering on “the outcome of any election for any public office both within and without the state of Nevada.”

In 2011, the gaming board allowed sportsbooks to petition for approval on individual nonsports wagers, if the events were supervised, verifiable and “consistent with the public policy of the state,” along with a few other criteria. That led to a few new bets on events such as the Cy Young winners, the World Series of Poker and the Heisman Trophy winner. But even though events like the Oscars and “American Idol” have been mentioned as candidates, they haven’t been approved.

A.G. Burnett, chairman of the NGCB since 2012, doesn’t see this list growing significantly soon, largely because the board wants to make sure the events are truly fair.

“At the end of the day what we care about is two things, the state’s reputation and also, of course, patrons,” Burnett said in an interview. “Making sure patrons are protected and always get a fair shake when they place a wager.”

The board is also considering allowing betting on eSports, but Burnett admitted there is still work to be done.

“We have a high level of comfort with our sportsbooks,” he said, “but we also have to have a level of comfort with the eSport event itself. We need to know who it is run by and that it’s run by people that care about integrity and focusing on a good, clean event.” Last month, after our interview, Burnett said publicly that he was getting more comfortable with the idea of eSports betting, and said it might be approved before the end of the year.

Some sportsbook managers are chafing at the restrictions and favor adding new events, arguing that the less-reputable characters who used to run gambling in Las Vegas have been replaced by more reliable large corporations.

“There have been so many layers of regulations just to get into the business,” said Chris Andrews, who manages the book at the South Point Hotel and Casino. “There are just not as many opportunities for some of that old stuff to happen again.”

Andrews would love to get in on the presidential-election action, and he wishes the gaming board would agree with him that allowing political bets would increase turnout at the polls.

“If people could bet on the election, yeah, it would spur voting,” he said. “If you bet $100, $10 or $10,000, whatever, you would go vote for your [candidate].” But while sportsbooks are primarily mainstream corporate entities today, the perception of gambling as an unsavory vice means the intersection of gambling and politics may be more than the gaming regulators are willing to approve.

In 2013, a proposal was put to the Nevada Legislature to allow gambling on elections but it didn’t go anywhere. Burnett wasn’t on the NGCB when the original rules were passed banning election gambling but said he understands the ultimate decision.

“Let’s keep elections separate and distinct from sports and games that people play,” he said. “God forbid if anything happened that would put a bad taint on it.”