Opening arguments took place in a D.C. courtroom Tuesday in the closely watched antitrust case brought by the federal government and 38 states and territories against Google. They accuse Google of illegally protecting its search engine monopoly by paying billions of dollars to Apple and other smartphone companies and web browsers to be their default search engine. It’s the largest antitrust lawsuit brought by the U.S. government against a major tech company since the Justice Department sued Microsoft over 20 years ago.

U.S. District Judge Amit Mehta is presiding over the case. He could theoretically order the breakup of Google should the company lose, though analysts say it’s more likely Google would be forced to change its business practices. A loss for the government could have implications for its ability to regulate tech and other industry monopolies. The trial is expected to last 10 weeks.