A federal judge in California has issued a preliminary injunction blocking the proposed $6.2 billion merger between Nexstar Media Group and TEGNA, handing enforcers and private challengers a significant early win in one of the most closely watched media antitrust fights in recent years.

The court found that the plaintiffs — including multiple state attorneys general and DirecTV — were likely to succeed on claims that the transaction would lessen competition, giving the combined company greater leverage over distributors and potentially leading to higher prices or worse terms that could ultimately affect consumers.