As two of the US’s largest telecom companies seek to join forces, state attorneys general are seeking to stop them, for fear of creating a company that will violate anti-competition law.

T-Mobile and Sprint are seeking a merger valued at $26.5 billion in a federal trial due to begin this week in Manhattan, presided over by US Judge Victor Marrero. The judge will listen to arguments against the merger from lawyers representing a group of states, including New York and California, who will say that such a merger will interfere with competition, ending with higher prices for consumers.

The states will assert that it would be a blow to competition to make what is already a small field of four competitors, Verizon, T-Mobile, Sprint and AT&T and shrink it down to only three. Even though the Federal Communications Commission and the Department of Justice both ruled in favor of the merger, the states want to argue that the decisions were mistakes and the deal should be prevented.

Spring and T-Mobile lawyers also have reasons to allow the merger, saying that a few crucial things have changed over the years which make a merger more competitive and helpful for consumers.