The United States District Court for the Eastern District of California issued the order, "preventing Nexstar and Tegna from integrating and consolidating their assets as part of the merger," according to the attorney general's office. James and the attorneys general of California, Colorado, Connecticut, Illinois, North Carolina, Oregon, and Virginia filed the underlying suit on March 19.

"Nexstar's merger with Tegna illegally eliminates competition, and today we won a critical victory in our effort to enforce the law and stop this merger from moving forward," James said in the statement. "We will keep fighting our case to ensure fair competition among local TV stations that serve communities across the country."

The coalition alleges the combination would produce a company controlling over 250 local TV stations that reach 80 percent of the U.S. population, according to the release. Nexstar currently controls more than 200 stations in 116 markets, and Tegna, the fourth-largest broadcasting group, operates 64 stations across 51 markets, the attorney general's office said.

Thirty-one media markets where the two companies own competing stations — including Buffalo, New York — would "see diminished competition" if the merger closed, the release said. The states argue the deal would significantly eliminate competition among local affiliates of ABC, CBS, NBC, and FOX.

"Consolidating hundreds of local TV stations under one corporate owner would mean higher prices and lower quality programming for consumers," James said.

The states allege the combined company would gain leverage to raise retransmission fees charged to cable providers, costs they say would be passed to subscribers, and could black out channels for providers that refuse to pay higher fees, according to the release. The suit also alleges the merger would degrade local news quality by eliminating newsrooms in markets where Nexstar owns multiple stations.

The court previously granted a temporary restraining order in a separate lawsuit filed by DirecTV, and that case has been combined with the states' action, the attorney general's office said.

For New York, Assistant Attorney General Morgan Feder and OAG Fellow Jaya Mantovani handled the matter under the supervision of Deputy Bureau Chief Amy McFarlane and Bureau Chief Elinor Hoffmann of the Antitrust Bureau.