After half a decade fighting to keep its empire together, Google’s defenses are wearing thin.

The company is facing a two-front war that could fundamentally reshape its business, and, the US Department of Justice argues, open new opportunities for its competitors. Last year a federal judge deemed Google an unlawful monopolist in the online search market, and this past week, a different judge declared it had monopolized the ad tech market, too. On Monday, it will face a new stage in that first battle: a three-week trial in Washington, DC to determine the appropriate remedies to restore competition to online search.

Google has vowed to appeal both rulings, but it can’t do so until after it’s gone through remedies trials for each case, letting the DOJ argue for its breakup and other restraints. In court starting Monday, the government will make the case for forcing Google to sell its Chrome web browser, share search data with competitors, keep the government abreast of new AI investments, and end exclusionary deals with browser and phone makers.

In this and the coming ad-tech remedies trial, the judges may find that less extreme measures can address the harms they believe Google inflicted. But it’s still the greatest antitrust threat a major tech company has faced in the US for decades — since Microsoft’s landmark loss over its PC operating system monopoly 25 years ago.

Outside the US, Google has incurred fines for anticompetition charges and had to make business changes to comply with international regulations. But none of these have approached what the DOJ is asking for. If the DOJ gets its way, Google and Apple could end one of the most lucrative partnerships in Silicon Valley, while rivals like Microsoft could get access to some of Google’s most valuable data.

During the first phase of the US antitrust trials, known as the liability phase, Google was defiant in arguing that it has competed fairly to win users with its superior products. In this next phase, Google will be facing judges who have already determined that’s not the case — and Google will be forced to argue for simply limiting the penalties.

The DOJ believes that serious measures are necessary to bust up Google’s search monopoly. Google’s exclusionary deals with Apple, it’s argued, made it exceedingly difficult for even quality competitors to break through. Owning Chrome lets Google control one of the major access points for search engines. And Google search’s popularity means users give it huge volumes of query data that competitors don’t have.

The DOJ also wants to ensure any remedies imposed by the court are future-proof so Google can’t regain monopoly power later on. That’s why it’s included a focus on AI, which it worries could become a major search platform. The government backed off of its request for Google to sell its AI investments after President Donald Trump took office, but it still wants to require the company to notify the government about future investments in the space.

The court will hear from Google executives involved in its Search, Android, and Chrome businesses, as well as executives from online search competitors like DuckDuckGo, Microsoft’s Bing, and Yahoo. AI executives from companies like OpenAI and Perplexity will weigh in as well. Witnesses last time testified about whether Google had taken anticompetitive moves in a definable market; this time the government will use them to argue for why its proposed fixes are important — while Google will argue they could break tools consumers enjoy.

Virginia-based Judge Leonie Binkema has not yet set trial dates for the remedies proceedings in the ad tech case. But in the coming months, both sides will present their wishlists for changing how the company works.

These remedies will likely be more straightforward than those in the Search case. Brinkema agreed with DOJ arguments that Google monopolizes markets through two illegally tied services: a publisher ad server known as DFP and its ad exchange AdX. (She agreed with Google on one count — that it did not have a monopoly in the market for its advertiser-side tools.) The government could reasonably seek to make Google split off one or both.

That might feel less dramatic than a Chrome spin-off. But the ad market Google dominates underlies large parts of the internet economy — it’s where publishers can make money outside big social networks. And these publishers testified throughout the trial that they’re chafing under Google’s whims. Making that ecosystem more competitive could revitalize the open web.

Mehta could rule by the end of the summer on search remedies. And Brinkema — who’s on a court that’s nicknamed the “rocket docket” for its comparatively speedy pace — could also possibly set a trial and make a ruling this year. But Google could push any tangible changes out for years. The company has vowed to appeal the decisions, a route that could take it all the way up to the Supreme Court. Trump’s DOJ could also decide to settle either case, although since several states are also tied into the lawsuits, they could pursue remedies themselves.
Microsoft’s big antitrust loss, famously, didn’t result in a breakup. As George W. Bush’s administration took over the case in 2001, it settled for milder remedies. Even so, experts say the landscape opened up for new, innovative companies. One of those said to be one of the biggest beneficiaries? Google.