The two companies completed the merger in the days following the ruling, so if the government prevails, the appeals court could order the deal undone or require AT&T to sell off parts of Time Warner. 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". AT&T said it was prepared to defend the case on appeal. He also strongly suggested that the Justice Department not to seek a stay to block the merger as it pursued an appeal.
"They have the right to appeal".
"The Court's decision could hardly have been more thorough, fact-based, and well-reasoned", McAtee said in a statement. The transition to streaming services, away from traditional cable, is one that's costing pay TV companies millions of subscribers and billions in revenue every year.
Mr Trump has publicly feuded with Time Warner's CNN, calling it "failing" and a purveyor of "fake news".
However, that apparently was not enough to satisfy the DoJ, which declined to comment. AT&T has committed to certain conditions under which it will run Time Warner's Turner Broadcasting, which includes CNN.
In addition, AT&T Communications will have no say in setting Turner's prices or other terms in contracts with companies that distribute its content.
Media commentators suggested Trump was critical of the deal because of his antipathy for CNN, which has lambasted his presidency and is a regular target for his Twitter attacks.
Delrahim and DOJ-Antitrust's suit against the AT&T-Time Warner merger bucked this trend, seeking to establish a norm against some vertical integration in the era of tech giants that increasingly offer products up and down the supply chain.