The US Justice Department and a coalition of state attorneys general launched an antitrust case against Google in Washington on Tuesday.

The technology giant is accused of unlawfully abusing its dominance in the search engine market in order to maintain its monopoly power.

This dominance has made Google parent company Alphabet one of the richest companies in the world. Search ads generate nearly 60 percent of the company's revenue, dwarfing revenue from other activities like YouTube or Android phones.

The trial is the largest US antitrust case against a major technology company since the same department took on Microsoft over the dominance of its Windows operating system more than two decades ago. The lawsuit against Google was filed in 2020.

What does the US accuse Google of?

The US Justice Department is expected to detail how Google unlawfully stifled competition by paying billions of dollars to device makers like Apple Inc., wireless companies like AT&T and browser makers like Mozilla to ensure its search engine would be the default on most phones and web browsers.

The government's lawsuit alleges that these deals were intended by Google to be "exclusionary" because they left rivals no chance to compete and allowed the tech giant to consolidate its market dominance. Google has a 90% market share of the internet search market in the United States and across the globe.

The government also said the browser agreements had resulted in less choice for consumers and less innovation. "Two decades ago, Google became the darling of Silicon Valley as a scrappy start-up with an innovative way to search the emerging internet," the Justice Department said in its lawsuit. "That Google is long gone."

What has Google said?

The tech giant claims it has not violated antitrust laws. In a January court filing, Google said its browser agreements constituted "legitimate competition" and not "unlawful exclusion."

The company argues that it is successful not because it broke the law, but because it gave consumers a fast, effective search engine for free.

"In sum, people don't use Google because they have to — they use it because they want to,"  Kent Walker, Google president of global affairs, said in a blog post.

Google's lawyers argue that consumers can delete the Google app from their devices or simply type Microsoft's Bing, Yahoo or DuckDuckGo into a browser to use an alternative search engine.

What happens to Google if it loses?

Judge Amit Mehta's verdict is expected many months after about three months of expected hearings. The trial, which begins Tuesday with opening statements, consists of two phases.

In the first case, Mehta will decide whether Google violated antitrust law in its management of search engines and search advertising.

If he concludes that Google has violated the law, a further trial will decide what steps should be taken, such as breaking up Google's businesses or reshaping the way the company operates.

Whatever the outcome, the ruling will almost certainly be appealed by both sides, potentially delaying the case for years.

Previous major antitrust cases included Microsoft (filed in 1998) and AT&T (1974). The breakup of AT&T in 1982 is considered to have paved the way for the modern cell phone industry, while the battle with Microsoft opened the space for Google and others on the internet.

The case against Microsoft ended in a settlement in 2001 after an appeal reversed an order that the company be split up.

dh/jcg (AFP, AP, Reuters)