The bedrock of Google's empire sustained a major blow on Monday after a judge found its search and ad businesses violated antitrust law. The ruling, made by the District of Columbia's Judge Amit Mehta, sided with the US Justice Department and a group of states in a set of cases alleging the tech giant abused its dominance in online search. "Google is a monopolist, and it has acted as one to maintain its monopoly," Mehta wrote in his ruling. The findings, if upheld, could outlaw contracts that for years all but assured Google's dominance. Judge Mehta ruled that Google violated antitrust law in the markets for "general search" and "general search text" ads, which are the ads that appear at the top of the search results page. Apple, Amazon, and Meta are defending themselves against a series of other federal- and state-led antitrust suits, some of which make similar claims. Google's disputed behavior revolved around contracts it entered into with manufacturers of computer devices and mobile devices, as well as with browser services, browser developers, and wireless carriers. These contracts, the government claimed, violated antitrust laws because they made Google the mandatory default search provider. Companies that entered into those exclusive contracts have included Apple, LG, Samsung, AT&T, T-Mobile, Verizon, and Mozilla. Those deals are why smartphones ... come preloaded with Google's various apps.