WASHINGTON — How you watch “Game of Thrones” and CNN is about to have its day in court.

The Justice Department’s bid to block AT&T’s $85 billion merger with Time Warner is set to head to trial next week, in one of the most anticipated antitrust battles in years.

The deal, if approved, would create a media giant that combines AT&T’s nationwide mobile and satellite distribution networks with Time Warner’s huge collection of popular movies and television offerings, including “Game of Thrones” on HBO, news on CNN and college and professional basketball on TNT. The central question of the trial: Would that combination hurt consumers or help them?

How the judge rules in the case has the potential to shape the fast-changing business of video, as consumers increasing turn to streaming services instead of traditional cable TV. AT&T, a nationwide satellite TV and wireless provider, argues that pairing up with a major content company is necessary to compete against the reach and resources of tech giants like Netflix and Amazon. But the Justice Department says the deal would hurt upstart streaming services and lead to higher prices for consumers.

The decision will frame the competition among Silicon Valley, Hollywood and Madison Avenue, while also establishing what kinds of corporate mergers — in the media industry and beyond — will be permitted in the years to come.