Google pays Apple billions a year to use its search engine. Now executives must testify.

Judge Amit Mehta will consider legal questions that are both wonky and technical. Being a monopoly is not illegal, but abusing such power to quash competition is. The Justice Department is arguing that Google strong-armed Apple and other smartphone makers into these deals. "The exclusive default was not Apple's choice," Dintzer told the court last week, citing Apple's interest in also dealing with Yahoo, before Google demanded exclusivity.