The Justice Department said on Monday that the best way to address Google’s monopoly in internet search was to break up the $1.81 trillion company, kicking off a three-week hearing that could reshape the technology giant and alter the power players in Silicon Valley.

Judge Amit P. Mehta of the U.S. District Court for the District of Columbia ruled in August that Google had broken antitrust laws to maintain its dominance in online search. He is now hearing arguments from the government and the company over how to best fix Google’s monopoly and is expected to order those measures, referred to as “remedies,” by the end of the summer.

In an opening statement in the hearing on Monday, the government said Judge Mehta should force Google to sell its popular Chrome web browser, which drives users to its search engine. Government lawyers also said the company should take steps to give competitors a leg up if the court wants to restore competition to the moribund market for online search.

“Your honor, we are not here for a Pyrrhic victory,” David Dahlquist, a Justice Department lawyer, said in his opening statement. “This is the time for the court to tell Google and all other monopolists who are out there listening, and they are listening, that there are consequences when you break the antitrust laws.”

The outcome in the case, U.S. v. Google, could drastically change the Silicon Valley behemoth. Google faces mounting challenges, including a breakup of its ad technology business after a different federal judge ruled last week that the company held a monopoly over some of the tools that websites use to sell open ad space. In 2023, Google also lost an antitrust suit brought by the maker of the video game Fortnite, which accused the tech giant of violating competition laws with its Play app store.

The legal troubles could hurt Google as it battles OpenAI, Microsoft and Meta to lead a new era of artificial intelligence. Google has increasingly woven A.I. into its search. But the Justice Department has told Judge Mehta he should make sure Google cannot parlay its search monopoly into similar dominance in A.I.