The US government filed a blockbuster lawsuit Tuesday accusing Google of maintaining an "illegal monopoly" in online search and advertising in the country's biggest antitrust case in decades -- and opening the door to a potential breakup of the Silicon Valley titan.
The politically-charged case, which could take years to play out, draws new battle lines between the US government and Big Tech with potentially major implications for the sector.
Deputy Attorney General Jeffrey Rosen said the case filed with Republican state attorneys general from 11 states takes aim at Google's dominance of the online ecosystem.
"Google is the gateway to the internet," Rosen told reporters.
"But it has maintained its monopoly through exclusionary practices that are harmful to competition."
The suit said these agreements include long-term agreements requiring that Google search be pre-loaded on devices and making it impossible to delete some of its apps.
The government claims Google pays billions to maintain that position, thus reinforcing its monopoly position.
The lawsuit filed in Washington contends that Google's actions shut out competitors and proposes that the court consider a range of remedies including a possible breakup, offering few specifics.
The filing calls for the court to "enjoin Google" from anticompetitive practices and consider "structural relief as needed to cure any anticompetitive harm," which would mean structural changes to the tech giant.
Asked about how officials would seek to break up Google, Rosen said the litigation would have to "proceed a little further before we would want to set out specifics."
Google called the lawsuit "deeply flawed."
"People use Google because they choose to -- not because they're forced to or because they can't find alternatives."
The move comes after months of investigations by US federal and state antitrust enforcers seeking to check the company's power and parallel probes into other titans such as Amazon, Facebook and Apple.
Progressives have accused the firms of stifling competition and worsening economic inequality. A recent House of Representatives report suggested Google and others should be broken up to preserve competition.
Conservatives have accused them of political bias, although evidence has been scant.
More to come?
"Today's review is a milestone but not a stopping point," Rosen said.
"We plan to continue our review of competitive practices by leading online platforms."
A longtime Big Tech critic, Republican Senator Josh Hawley of Missouri, said the case would be "the most important antitrust suit in a generation," and welcomed the Justice Department move.
The main unit of holding firm Alphabet, Google operates the dominant search engine used in most of the world and a variety of related services such as maps, email, advertising and shopping.
It also operates the Android mobile operating system used on the majority of smartphones worldwide.
Google has been hit with big fines in the European Union for unfair competition, and has challenged those cases. The company has consistently denied claims of monopoly abuse.
Michael Carrier, a Rutgers University law professor specializing in antitrust issues, said the case could seek to force Google to remove some of its software from Android phones, and in that sense would be similar to the Microsoft case of the 1990s where customers were forced to use proprietary programs.
But Carrier said the filing just two weeks before the election "raises the possibility that political concerns are playing a role here."
The case is the most high-profile since the action filed against Microsoft in 1998 and could be a test case for antitrust.
To win in court, the government will need to overcome a long standard of antitrust law that cases must show consumers are harmed by monopolistic practices.
Google and its supporters will argue that consumers benefit from the free services it offers even if some competitors are disadvantaged.
"One reason the US technology sector is the envy of the world is antitrust policy that encourages dynamic markets that reward innovators and disrupt sluggish competitors," said Matt Schruers of the Computer & Communications Industry Association, a trade group which includes Google.
"It cannot escape notice that this suit was hurried out on the eve of an election where the administration has aggressively pressured tech companies to take actions in its favor. Antitrust law should be driven by consumers' interests, not political imperatives."
Robert Atkinson of the Information Technology and Innovation Foundation, said the DOJ "should avoid structural remedies, which are often grounded in a 'big is bad' antimonopoly ideology without considering the broader implications that such a policy would have on innovation."
Justice Department officials argue that the lack of competition "harms users, advertisers, and small businesses" and limits innovation.