The Department of Justice (DOJ) made its pitch at a hearing before District Judge Amit Mehta, who is considering "remedies" after making a landmark decision last year that Google maintained an illegal monopoly in online search.

"Nothing less than the future of the internet is at stake here," Assistant Attorney General Gail Slater said prior to the start of the hearing in Washington.

"If Google's conduct is not remedied, it will control much of the internet for the next decade and not just in internet search, but in new technologies like artificial intelligence."

Google is among the tech companies investing heavily to be among the leader in AI, and is weaving the technology into search and other online offerings.

Google countered in the case that the United States has gone way beyond the scope of the suit by recommending a spinoff of its widely used Chrome, and holding open the option to force a sale of its Android mobile operating system.

The legal case focused on Google's agreements with partners such as Apple and Samsung to distribute its search tools, noted Google president of global affairs Kent Walker.

"The DOJ chose to push a radical interventionist agenda that would harm Americans and America's global technology leadership," Walker wrote in a blog post.

"The DOJ's wildly overbroad proposal goes miles beyond the Court's decision."

The DOJ case against Google regarding its dominance in internet search was filed in 2020.

Judge Mehta ruled against Google in August 2024.

- Ad tech under fire -

Google's battle to protect Chrome renewed just days after a different US judge ruled this month that it wielded monopoly power in the online ad technology market, in a legal blow that could rattle the tech giant's revenue engine.

The federal government and more than a dozen US states filed the antitrust suit against Alphabet-owned Google, accusing it of acting illegally to dominate three sectors of digital advertising -- publisher ad servers, advertiser tools, and ad exchanges.

The vast majority of websites use Google ad software products that, combined, leave no way for publishers to escape Google's advertising technology, the plaintiffs alleged.

District Court Judge Leonie Brinkema agreed with most of that reasoning, ruling that Google built an illegal monopoly over ad software and tools used by publishers, but partially dismissed the argument related to tools used by advertisers.

"Google has willfully engaged in a series of anticompetitive acts to acquire and maintain monopoly power in the publisher ad server and ad exchange markets for open-web display advertising," Brinkema said in her ruling.

The judge concluded that Google further entrenched its monopoly power with anticompetitive customer policies and by eliminating desirable product features.

Online advertising is the driving engine of Google's fortune and pays for widely used online services like Maps, Gmail, and search offered free.

Money pouring into Google's coffers also allows the Silicon Valley company to spend billions of dollars on its artificial intelligence efforts.

Combined, the courtroom defeats have the potential to leave Google split up and its influence curbed.

Google said it is appealing both rulings.