The ruling by a federal judge, Leonie Brinkema, in an antitrust case over Google’s advertising technology could add to the internet company’s woes.

The Justice Department and Google are set to make closing arguments in a trial alleging Google’s online advertising technology constitutes an illegal monopoly

Google, already facing a possible breakup of the company over its ubiquitous search engine, is fighting to beat back another attack by the US Department of Justice alleging monopolistic conduct, this time over technology that puts online advertising in front of consumers.