Google will confront an existential threat Monday as the U.S. government tries to break up the company as punishment for turning its revolutionary search engine into a ruthless monopoly.

The drama will unfold in a Washington courtroom during the next three weeks during hearings that will determine how the company should be penalized for operating an illegal monopoly in search. The proceedings, known in legal parlance as a "remedy hearing," feature a parade of witnesses that includes Google CEO Sundar Pichai.

The U.S. Department of Justice is asking a federal judge to order a radical shake-up that would ban Google from striking the multibillion dollar deals with Apple and other tech companies that shield its search engine from competition, share its repository of valuable user data with rivals and force a sale of its popular Chrome browser.

The moment of reckoning comes four-and-half-years after the Justice Department filed a landmark lawsuit alleging Google's search engine had been abusing its power as the internet's main gateway to stifle competition and innovation for more than a decade.

After the case finally went to trial in 2023, a federal judge last year ruled Google had been making anti-competitive deals to lock in its search engine as the go-to place for digital information on the iPhone, personal computers and other widely used devices, including those running on its own Android software.

That landmark ruling by U.S. District Judge Amit Mehta sets up a high-stakes drama that will determine the penalties for Google's misconduct in a search market that it has defined since Larry Page and Sergey Brin founded the company in a Silicon Valley garage in 1998.

Since that austere start, Google has expanded far beyond search to become a powerhouse in email, digital mapping, online video, web browsing, smartphone software and data centers.

Seizing upon its victory in the search case, the Justice Department is now setting out to prove that radical steps must be taken to rein in Google and its corporate parent, Alphabet Inc.

"Google's illegal conduct has created an economic goliath, one that wreaks havoc over the marketplace to ensure that -- no matter what occurs -- Google always wins," the Justice Department argued in documents outlining its proposed penalties. "The American people thus are forced to accept the unbridled demands and shifting, ideological preferences of an economic leviathan in return for a search engine the public may enjoy."

Although the proposed penalties were originally made under President Joe Biden's term, they are still being embraced by the Justice Department under President Donald Trump, whose first administration filed the case against Google. Since the change in administrations, the Justice Department has also attempted to cast Google's immense power as a threat to freedom, too.

"The American dream is about higher values than just cheap goods and 'free' online services," the Justice Department wrote in a March 7 filing with Mehta. "These values include freedom of speech, freedom of association, freedom to innovate, and freedom to compete in a market undistorted by the controlling hand of a monopolist."

Google is arguing the government's proposed changes are unwarranted under a ruling that its search engine popularity among consumers is one of the main reasons it has become so dominant.

The "unprecedented array of proposed remedies would harm consumers and innovation, as well as future competition in search and search ads in addition to numerous other adjacent markets," Google lawyers said in a filing leading up to hearings. "They bear little or no relationship to the conduct found anticompetitive, and are contrary to the law."

Google also is sounding alarms about the proposed requirements to share online search data with rivals and the proposed sale of Chrome posing privacy and security risks. "The breadth and depth of the proposed remedies risks doing significant damage to a complex ecosystem. Some of the proposed remedies would imperil browser developers and jeopardize the digital security of millions of consumers."

The showdown over Google's fate marks the climax of the biggest antitrust case in the U.S. since the Justice Department sued Microsoft in the late 1990s for leveraging its Windows software for personal computers to crush potential rivals.

The Microsoft battle culminated in a federal judge declaring the company an illegal monopoly and ordering a partial breakup -- a remedy that was eventually overturned by an appeals court.

Google intends to file an appeal of Mehta's ruling from last year that branded its search engine as an illegal monopoly but can't do so until the remedy hearings are completed. After closing arguments are presented in late May, Mehta intends to make his decision on the remedies before Labor Day.

The search case marked the first in a succession of antitrust cases that have been brought against a litany of tech giants that include Facebook and Instagram parent Meta Platforms, which is currently fighting allegations of running an illegal monopoly in social media in another Washington D.C. trial. Other antitrust cases have been brought against both Apple and Amazon, too.

The Justice Department also targeted Google's digital advertising network in a separate antitrust case that resulted last week in another federal judge's decision that found the company was abusing its power in that market, too. That ruling means Google will be heading into another remedy hearing that could once again raise the specter of a breakup later this year or early next year.