Sen. Maria Cantwell, D-Wash., on Wednesday warned colleagues that a House-backed bill to regulate college athletics would solidify an ‘‘unsustainable, distorted system’’ that favors the nation’s largest conferences and deepens existing financial divides.

In a letter to members of the Senate Commerce Committee, where she is the ranking member, Cantwell singled out the SCORE Act — scheduled for a House floor vote next week — saying it would give the NCAA a limited antitrust exemption, override state laws on compensating athletes in favor of a single national standard and strip away the possibility that student-athletes could be classified as employees of their schools.

Cantwell argued that the bill would ‘‘entrench a college sports arms race that rewards power conferences at the expense of smaller schools and conferences, student athletes and America’s future Olympic competitiveness.’’ She described the Big Ten and Southeastern Conference as the ‘‘Big 2’’ that would benefit most under the proposed law.

Attached to her letter was a report that quantified the growing gap between the Power Four conferences and other Division I leagues. The report said Power conferences are projected to receive an average of $63 million more than other conferences from the College Football Playoff in 2025 — an increase of $20 million in the gap since the CFP began after the 2014–15 season. The analysis also cited a near 70% increase in men's basketball spending by the Big Ten and SEC since 2023 and a surge in at-large bids for those conferences during last season's NCAA tournament.

"This dominance also heightens the risk of the SEC and Big Ten demanding a greater share of TV rights revenue for the tournament when the current TV media rights deal expires in 2032, or even leaving the NCAA altogether," the report said. It added that the widening divide could undermine the tournament's unpredictability and deprive fans of traditional "Cinderella" stories.

Supporters of the SCORE Act, including the NCAA and its most prominent conferences, say the legislation would create a consistent national framework for college athletics, resolving a patchwork of state laws and legal uncertainty surrounding athlete compensation and conference business arrangements. Opponents argue the bill would cement advantages for already powerful conferences and reduce competition.

The House bill has bipartisan backing, but Cantwell noted that a handful of House Republicans have expressed opposition. If the measure clears the House, it would face a tougher path in the Senate: if considered as a standalone piece of legislation, it would need 60 votes to overcome a filibuster.

The debate over the SCORE Act also intersects with separate lobbying efforts aimed at redistributing television revenue. Cody Campbell, a billionaire member of the Texas Tech board of regents, is running ads during college games urging lawmakers to amend a law that prevents conferences from pooling TV rights — an idea supporters say could help level the financial playing field across Division I. Cantwell's report did not address Campbell's proposal, but it notes similar concerns about concentrated power and revenue among the largest conferences.

Cantwell closed her letter by calling for lawmakers to pursue alternatives to the SCORE Act that would foster broader growth across college athletics. "I look forward to working with you to develop a more durable growth model for college athletics that will provide opportunities and reward all student athletes, increase audiences and revenues for college sports, and preserve women’s and Olympic sports," she wrote.

As the House prepares to vote, Congress faces competing pressures from university leaders, conference officials, athletes, advocates and commercial partners. The outcome will shape how colleges, conferences and the NCAA distribute revenue, define athlete status and govern relations with broadcasters and sponsors for years to come.