The Trump administration's renewed battle against AT&T's Time Warner deal signals that it still sees a path to undoing the blockbuster merger,  even after a stinging rebuke of its case last month.

Rather than walk away, the Justice Department's antitrust division took a big gamble Thursday with a one-sentence notice of appeal filed in federal court in Washington. In doing so, it risks a second defeat that could lead to binding precedent that makes future merger challenges harder.

But the move offers a tempting shot at redemption after a humiliating loss handed down by U.S. District Judge Richard Leon. The case will be heard by the U.S. Court of Appeals for the District of Columbia Circuit, where President Trump's recent Supreme Court nominee, Brett Kavanaugh, still sits.

"Their assessment of the strategic risks may be bad, may be unduly risky — a lot of people said that about this case in the first place," said Chris Sagers, an antitrust law professor at Cleveland State University. "So far, that has all proven true, and maybe it will prove true that appealing this decision was also unwise."

A Justice Department win at the appeals level would vindicate the decision by the head of the antitrust division, Makan Delrahim, to challenge the Time Warner takeover in the first place. The case has been closely watched because it's the first time in decades a court has weighed in on a merger of companies that operate in different parts of a supply chain. It was also the first major merger challenge under Trump, who vowed to oppose the tie-up when it was announced during the 2016 campaign. As president, he has relentlessly attacked Time Warner's CNN for its news coverage.

In last month's 172-page opinion, Leon ripped apart the government's case that the $85 billion deal would give AT&T the power to hike prices. The Justice Department argued that the telecom giant would charge its cable-TV competitors more money for Time Warner shows, bringing higher bills to consumers across the country.

To some observers, the judge's decision smacked at times of antigovernment bias — particularly when Leon admonished Justice Department lawyers to not bother seeking a temporary order halting the merger from proceeding. Obtaining a stay, which the government had a right to seek, "would undermine the faith in our system of justice," Leon wrote.

"The judge's ruling showed an extreme favoritism for AT&T's arguments and appeared to substantially discount everything the government presented," said Gene Kimmelman, head of Public Knowledge, a Washington-based public policy group that opposed the merger. "I'm not surprised the government views it as a totally incorrect ruling."

AT&T closed the Time Warner transaction on June 14, two days after Leon's ruling. The Justice Department had agreed not to seek an emergency court order preventing the deal from closing after AT&T promised to operate Time Warner's Turner Broadcasting as a separate business unit until 2019. That would make it easier for AT&T to sell Turner if the government ultimately prevails.

The stakes are high for both sides. The Time Warner case marked new ground for how antitrust enforcers deal with mergers of companies that operate in different parts of an industry's supply, known as vertical deals. For years, such tie-ups were approved with conditions on how the companies operate. Delrahim said last year he was breaking with that practice and would demand the sale of business units — so-called structural remedies — to address competitive harm.

Leon's decision could make that approach harder, according to lawyers. And the ruling is expected to help usher in a wave of deals. In fact, Comcast Corp. announced a $65 billion bid for 21st Century Fox Inc.'s entertainment assets the following day.

Stemming that tide won't be easy for the Justice Department.

"It's an uphill climb for the DOJ," said Jennifer Rie, an analyst at Bloomberg Intelligence in New York. "They seem to be adamantly against this kind of consolidation in media and seem to be really hell-bent on setting the precedent that vertical deals can be anticompetitive."

A win at the appeals court would give Delrahim freer rein, while a loss could set a binding precedent that would raise hurdles for tougher enforcement of vertical deals. The government faces long odds, according to lawyers, largely because Leon based his decision on his fact findings. Such decisions tend to be harder to reverse than those with errors in the application of the law.

Given that the Senate has said it'll move expeditiously on Kavanaugh's nomination, even were the case to be fast tracked it would be unlikely he would still be on the panel if he is confirmed. AT&T has said it would ultimately challenge any government win all the way to the Supreme Court, which has been favoring business in a series of recent rulings.

The notice of appeal doesn't detail the antitrust division's reasoning, and a spokesman for the department declined to comment.

"It's a challenging path for them, but it's not unreasonable for them to appeal," said Fiona Schaeffer, an antitrust lawyer at Milbank, Tweed, Hadley & McCloy in New York. "They must be confident in the merits of their case and believe that the judge misunderstood and misapplied their economic theory."

It's not unheard of for antitrust enforcers to lose a merger challenge and prevail on appeal. Leon plays the role of a "maverick," Sagers said, and that may set the stage for his decision to be undermined later.

"He's the character on the court," he said. "He writes these salty opinions that often take dramatic stands on things."

For its part, AT&T has vowed to maintain some distance from Time Warner until the matter is settled. In addition to keeping the Turner Broadcasting business separate, it's withholding input on pricing decisions, and adopting a fire wall that keeps information from flowing as freely between AT&T and Time Warner. If the appeals court sides with the Justice Department, AT&T could be forced to sell Turner.

But the Dallas-based company will keep fighting to preserve the merger. AT&T chief executive officer Randall Stephenson told reporters at a conference in Sun Valley, Idaho, that he expected the government's appeal and wasn't daunted by it.

"We'll take it to the Supreme Court if that's where it goes," he said.