WASHINGTON (AP) — Fighting to defend its $81 billion takeover of Time Warner from a government challenge, AT&T is arguing the Trump Justice Department has failed to show that the merger will raise prices for pay-TV programming and for the consumers who watch it.

The AT&T-Time Warner marriage was completed this spring soon after a federal judge approved it. But government antitrust regulators filed to have the judge's ruling overturned, setting the stage for a landmark competition case in the U.S. Court of Appeals in Washington.

In a filing Thursday, the phone and pay-TV giant asserted the merger will save it money on content from Time Warner's Turner Broadcasting, enabling it to cut charges to its DirecTV customers by at least $78 million a year.

U.S. District Judge Richard Leon was correct to dismiss the government's argument that the merger would hurt competition, limit choices and jack up prices for consumers to stream TV and movies, Dallas-based AT&T, the biggest pay-TV provider in the U.S., said in its filing.

The government "failed for multiple reasons to (show) that net retail prices will likely be higher than otherwise," the company said.

Leon's ruling in June opened the way for one of the biggest media deals ever. AT&T has since absorbed Time Warner, the owner of CNN, HBO, the Warner Bros. movie studio, "Game of Thrones," coveted sports programming and other "must-see" shows.

The Justice Department, however, has maintained that Leon was wrong in concluding the merger won't harm consumers and that he misunderstood the complexities of the booming pay-TV market and the nature of AT&T's competitors.

If the government were to prevail in its appeal, the complex merger might have to be unwound.

Many legal experts believe the government will have a hard time convincing the appeals court to overturn Leon's ruling. Opposing the merger forced the federal antitrust regulators to argue against standing legal doctrine that favors mergers among companies that don't compete directly with each other, what's known as a vertical merger.

The U.S. antitrust lawsuit against AT&T was the first time in decades that the government has challenged that doctrine by suing to block a vertical merger.

The government contends that this deal is different. By combining the programming content of Time Warner's Turner Broadcasting with AT&T's vast distribution network for its DirecTV, the combination will hurt competition and violate federal law, it says. AT&T claims about 25 million of the 90 million or so U.S. households that are pay-TV customers.

Even with a small chance of the government winning, the stakes are high and the case could affect the future course of antitrust regulation.

When the deal was first made public in October 2016, it drew fire from then-candidate Donald Trump, who promised to kill it "because it's too much concentration of power in the hands of too few." Trump has publicly feuded with Time Warner's CNN, calling it "failing" and a purveyor of "fake news." The president's statements didn't come up during the trial, though his antipathy loomed in the background.

Leon's ruling opened the floodgates to deal making in the fast-changing worlds of entertainment production and distribution.

Just a day after his decision, Comcast launched a $65 billion cash bid for the bulk of 21st Century Fox — topping Disney's all-stock $52.5 billion offer in December. Comcast later dropped that bid in order to focus on its attempted buyout of European pay-TV operator Sky.