The National Collegiate Athletic Association once had the tightest of clamps on college athlete compensation, maintaining a strict stance that any form of benefit that rewarded players for their participation would wreck a so-called “amateur model” that it had relied on for decades.

As the NCAA meets on Tuesday to determine a new vision for college sports, however, its ironclad hold on athlete compensation has been broken—and it has little leverage to retake control of the matter.

The Supreme Court ruled unanimously on Monday that the NCAA had violated antitrust law in a case about the range of permitted education-related benefits that college athletes can receive. In the future, the NCAA will now be subject to the same kind of scrutiny as other entities as to whether its rules unlawfully suppress competition. It can’t fall back on arguments that maintaining an amateur model is crucial to its product. 

“The NCAA is on its heels right now,” said Len Elmore, co-chair of the Knight Commission on Intercollegiate Athletics, an advocacy group that aims to reform inequities in college sports.

The decision marks a historic loss of control for an organization that for decades has maintained a narrow view of how athletes are compensated for playing college sports—and wielded a powerful enforcement club at those who violated them. It held the power to vacate titles and remove wins. 

As recently as last October, for example, the NCAA vacated three years of the University of Massachusetts, Amherst women’s tennis team’s wins over $9,100 compensation “in excess of full cost of attendance” to them and the men’s basketball team that included eight athletes continuing to receive a fee associated with dorm phones after they moved to off-campus housing. 

On its own, the Supreme Court decision will not stop the NCAA from continuing to make rules, which the association noted in a brief statement on Monday. But the association has already lost control of the debate going forward. That is because it also faces a wave of state laws that address far more sweeping compensation for college athletes than what is addressed in the Supreme Court ruling — the rights to own their name, image and likeness and sign endorsement deals with third parties.

At least seven of those laws are due to come into effect July 1. 

As the NCAA’s revenue has increased, the debate has intensified over what types of compensation should be considered for college athletes. WSJ explains how a combination of court cases, state legislation, and public pressure are expanding the scope of what it means to be an amateur athlete. Photo: Ronald Martinez/Getty Images (Video from 3/31/21)

The NCAA has told Congress that it’s unlikely to attempt to block the laws from coming into effect. It’s also said in a memo to schools sent last week that the association will not seek to punish schools in states that allow athletes to cut endorsement deals for following state laws. And Congress has made clear that it’s not going to pass a federal standard, at least before July 1, that would pre-empt the state laws. 

Instead, the NCAA is going to try to pass its own bylaw changes that grant some name, image and likeness rights to college athletes. Doing so would require the Division I Council to approve new rules when it meets on Tuesday and the NCAA Board of Governors to ratify the rules before July 1.  

Big 12 commissioner Bob Bowlsby, co-chair of the NCAA’s Legislative Solutions Group that proposed the new rules pertaining to name, image and likeness, said he was cautiously optimistic the association would be able to manage this. He also noted that it was “too early to tell” how Monday’s Supreme Court ruling would affect the effort.

Either way, it may not matter because of the arrival of the broad new state laws. Elmore and others are clear that, in cases where state laws go further than the NCAA rules, athletes will have the greater freedoms. And states have already made clear they are willing to enhance their laws, if needed, to keep up with their college sports rivals. 

“I think it’s going to be chaos, because there is not a real identification of a remedy for a situation like this that is coming up,” said Elmore.

NCAA President Mark Emmert said on Monday only that the association “committed to supporting NIL benefits for student-athletes” and that “we remain committed to working with Congress to chart a path forward, which is a point the Supreme Court expressly stated in its ruling.”

The states’ rush through the open door provided by the NCAA has also altered its prospects of tailoring any future federal law. That’s because some key lawmakers in the fight have said that they’re unwilling to eventually pass any federal standard that is weaker than the most pro-athlete state law. Many lawmakers also say they’re willing to take their time to pass a federal law in order to include other issues important to them, such as changes to athlete healthcare. 

The NCAA indicated that it planned to reverse course on endorsement rights back in October 2019. The about-face had come after California lawmakers passed a bill that would require schools to allow their athletes to earn endorsement and sponsorship money. The NCAA initially indicated it would seek to freeze out California from its events if the governor signed the bill. The governor signed the bill.

Then the promised new rules failed to materialize, in part because the association was wrangling with how to implement “guardrails” that would prevent deals with athletes from becoming booster payments in disguise, among other issues.

It also was fighting the case brought by former West Virginia University running back Shawne Alston and other former Division 1 athletes over education-related benefits. It expected that the ultimate decision from the Supreme Court there would establish how much latitude it might actually have to write those rules from an antitrust perspective. 

Waiting for the courts, though, came with a price. In the absence of a nationwide standard from the NCAA, states bolted to pass their own laws confirming endorsement rights for athletes within their borders. After Florida passed a law set to come into effect July 1, 2021, it set off a stampede from other states, all eager to avoid being one-upped in recruiting.

Now, high school athletes are relying on that as they make their choices.  

“Recruits and their families are thinking about this [NIL] in the recruiting process,” said Florida State senior associate athletic director Jim Curry, who oversees the university’s “Apex” program created this year to help Seminoles athletes navigate the new rules. 

“It’s clear to me that this is now part of the conversation.” 

Write to Louise Radnofsky at louise.radnofsky@wsj.com and Laine Higgins at laine.higgins@wsj.com