Explainer: Why is the US suing Google for antitrust violations?

The U.S. Justice Department and a coalition of state attorneys general on Tuesday will begin a blockbuster antitrust trial in Washington, alleging that Alphabet's (GOOGL.O) Google unlawfully abused its dominance in the search-engine market to maintain monopoly power.

Here is an explainer on the key issues in the case.

WHAT IS THE GOVERNMENT'S LEGAL THEORY?

The U.S. and its state allies contend Google unlawfully stifled competition by paying billions of dollars to Apple (AAPL.O) and other business partners to ensure its search engine would be the default on most phones and web browsers.

The government's lawsuit, filed in 2020 in federal court, alleges these deals were intended by Google to be "exclusionary," denying rivals access to search queries and clicks, and allowing Google to entrench its market dominance.