On ground level at the Harrah’s Philadelphia casino in Chester on Thursday afternoon, a scattered flock of geese hunkered down against the cold and pecked disconsolately at the withered infield of the harness track.

Just inside those doors, another small gathering spread out among the hundreds of stations in the simulcast race book and split its attention between the thin offerings from Gulfstream and the Fair Grounds. A lonely teller chewed gum at the front of the room, a sentinel guarding a game that, along with its clientele, is drifting toward obsolescence.

One floor above, however, where the music plays, the lights are bright, and the slot machines celebrate with the recorded sound of coins hitting a payout tray, the present and the future meet at the back of the long casino floor. The Book, which had its official opening Jan. 24, was taking Super Bowl bets, along with wagers on a full menu of other professional and college events, and the crowd is both younger and decidedly more lively than the horse handicappers beneath them.

“I’m intrigued by 4037,” one patron offered, pointing to a proposition bet on the long list of possible Super Bowl wagers. “I like that one."

The choice was simple enough: Will the first turnover of the game be an interception or a fumble? A bettor who chose “interception” had to risk $150 to win $100, or similar odds based on the amount wagered. A better who chose “fumble” would be rewarded with $130 for every $100 wagered.

“I like interception,” he said. “They’re going to be throwing the ball.”

A year ago, when the Eagles were about to play in the Super Bowl, none of this was taking place legally in the United States in a sticks-and-bricks location anywhere outside of Nevada. Maybe the national culture has not been greatly improved by the Supreme Court decision in May that struck down a federal law imposing a ban on most sports betting, but it certainly has changed things.

“It is still too early for us to draw any conclusions, but we definitely have heard great feedback from the customers that have experienced The Book so far,” Harrah’s general manager Chris Albrecht said.

The afternoon crowd was steady as it moved through the short line to the tellers’ windows. The Book, one of several sports wagering outlets operating in the Pennsylvania, New Jersey, and Delaware region, was built at the back of the long floor of slots and table games – you have to walk past that action, after all – and is anchored by a large bar area featuring a wall of television monitors. For featured games, which will be the case Sunday night, the entire wall can turn into one huge monitor.

“It will be rocking on Sunday,” a teller said. “We’re getting here by 8 in the morning.”

A semi-circle of lounge chairs is set back from the bar and the monitor wall. The Book took reservations for those places for the Super Bowl. A few steps back, there is a tight oval of blackjack and roulette tables just steps from the windows. Assuming the first turnover is an interception, a good time is guaranteed for all.

At the moment, sports betting is legal in eight states. A bill authorizing sports betting has been passed in two other states, and legislation has been introduced in another 27 states and the District of Columbia. No bill has been introduced in 14 states. Nevada took $156.8 million of action a year ago. Thanks to the Supreme Court, the estimate is that $325 million will be wagered by Sunday, whether at physical sports books or through their online outlets.

The Court, in a decision that would have delighted anti-Federalists like Thomas Jefferson, sided with a states-rights interpretation of the Constitution. Whether the framers, who were wrestling with issues like the establishment of a national bank, would defend the right of states to offer the proposition that Todd Gurley will score the first touchdown in a football game is unknown. Justice Stephen G. Breyer sided with the majority, but also wrote a partial dissent for the minority, which is sort of the judicial equivalent of playing the middle.

In any case, it happened, and the lights are on. Caesars Entertainment, which owns Harrah’s Philadelphia and operates several dozen casinos across the country, saw its stock price rise 6 percent the day of the Supreme Court ruling. That cannot be interpreted as a show of faith in the sports betting public.

At Harrah’s, all straight bets are 11-10. A bettor must risk $55 to win $50. The small matter of the missing $5, the “vigorish,” is why the lights are on. Those who set the lines for Caesars Entertainment, and for all casinos, do so in an attempt to place as close to 50 percent of the bettors on each side of a wager as possible. Books don’t judge sporting events. They judge the bettors. Half win, half lose, and the book keeps the vig. It’s a heck of a business.

“I like the Rams scoring under 29 ½,” another customer said, fingering a prop that cost $140 to win $100. “I don’t think they get that.”

The main betting lines for the Super Bowl, after an early course correction, stayed put at the Patriots favored by 2 ½ points, and the over/under at 56.5 points. The fact that the line didn’t move is an indication that it is a good one. Late money could alter it before the game, but probably not by much.

“I don’t really like the game,” said one more bettor, sitting at a high top on the edge of the action. “I can’t bet on [Tom] Brady and I can’t bet against him.”

It’s a conundrum, but not one that will keep people from the windows this weekend and into the evening on Sunday. A floor above the geese and the horseplayers, at the back of the long room of clanging machines, tumbling dice, and turning cards, the new game is open for business. As far as one can tell, business is pretty good.