The legalization of sports betting in the United States has been a hot topic, especially since the Supreme Court agreed in late June to hear New Jersey's appeal in the state's long-running quest to offer legalized sports betting.

It came to the forefront again Tuesday night in New York City when the commissioners of all four major U.S. sports leagues (Roger Goodell, Adam Silver, Rob Manfred, Gary Bettman) gathered for a panel titled "GameChangers: Creating the Future of Sports" at the Paley Center for Media.

"My sense is the law will change in the next few years in the United States," Silver said when asked about gambling.

He also stressed the importance of in-game wagering to fan engagement, noting, "People want to bet throughout the game ... It results in enormous additional engagement with the fans."

Silver, of course, is well known for his 2014 New York Times op-ed championing a federal approach to legalized sports betting in the United States. But one day before the op-ed, the NBA struck an equity deal with daily fantasy operator FanDuel and was in the center of the daily fantasy craze. The league has seen firsthand what in-game offerings can do for engagement.

Major League Baseball commissioner Manfred has also been more pro-legalization since he took over.

"If there's going to be a change in the regulatory structure with respects to sports gambling, we needed to be in a position to meaningfully engage and shape, try to shape what the new regulatory scheme looks like," Manfred told reporters last week.

On Tuesday night, he added: "There's a difference between someone betting on whether the next ball is a strike or betting on the outcome of a game."

The NHL has been traditionally quiet on the issue of legalization, but Bettman said he doesn't foresee a problem with the Las Vegas Golden Knights set to debut this upcoming season.

"We're a small part of betting compared to football and basketball," Bettman said. "... I don't worry about fixing games."

The NFL has been publicly opposed to legalization, but with the Oakland Raiders moving to Las Vegas in a few seasons, it will have to define its stance more clearly. Goodell didn't update the league's stance on Tuesday night.

The Supreme Court is expected to hear oral arguments in the New Jersey betting case sometime late this fall or early in 2018.