A coalition of 12 state attorneys general is suing to block the merger of Paramount Skydance and Warner Bros. Discovery (WBD), alleging the deal would harm movie theaters, basic cable distributors and audiences.

The coalition, led by California Attorney General Rob Bonta, maintains that the acquisition violates the Clayton Act, which prohibits mergers that could substantially lessen competition or tend to create a monopoly. The attorneys general allege that if the two companies are allowed to merge, it would lessen competition in three areas: theatrical distribution of wide-release films, “high-grossing” theatrical distribution and basic cable licenses.

The deal would combine two notable film studios, as well as streaming platforms Paramount+ and HBO Max. It would also create one of the largest television network portfolios, bringing together Paramount’s CBS and MTV with WBD’s CNN and HBO.

The proposed acquisition has already received scrutiny from filmmakers, actors and industry professionals who have argued that the deal would reduce competition and further consolidate the American media industry. Paramount has opposed this, saying that the combined film studios would release 30 films a year.

The states argue that, if approved, the deal would give Paramount significant control over key areas of the entertainment industry, including 27% of the U.S. movie distribution market, 30% of blockbuster movie distribution and 27% of the basic cable channel market.

“Consolidation here not only leads to higher prices, it also creates fewer opportunities for important stories to come to life and fewer ways for the public to find stories, ideas and perspectives beyond their own experiences,” Bonta said in a statement. “In this country, no one is above the law. With this lawsuit, California and our sister states are fighting for free and fair markets, not rigged markets. America has no kings in government or in our economy.”

Paramount CEO David Ellison had said in May that the transaction was on track to close in September. The deal received approval from WBD shareholders in April and was approved by the U.S. Department of Justice, which said the transaction is not likely to result in harm to competition or consumers.

The 11 states joining California are Arizona, Colorado, Connecticut, Massachusetts, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon and Washington.

Paramount and WBD did not immediately respond to TechCrunch’s requests for comment.