A federal trial begins today in Manhattan that will decide the future of Bellevue, Wash.-based T-Mobile’s pending merger with Sprint. It’s considered to be “among the most consequential in the history of the telecommunications industry,” per CNN. The case is expected to last 2-to-3 weeks, with a decision expected in February.

A coalition of more than a dozen states — which does not include Washington, T-Mobile’s home state — is challenging the $26 billion deal, arguing that it violates anti-competitive law.

States including New York and California say the merger, which would combine the nation’s No. 3 and No. 4 largest wireless carriers, will limit competition and raise prices. T-Mobile and Sprint argue that teaming up will help them battle Verizon and AT&T, the nation’s top carriers, and lower prices.

Texas and Nevada recently dropped out of the lawsuit after reaching settlements.

The Department of Justice and Federal Communications Commission approved the merger earlier this year thanks in part to last-minute concessions from the companies, including T-Mobile transferring assets to satellite TV provider Dish Network to create a new wireless carrier.

T-Mobile CEO John Legere will step down from the chief executive seat next year, effective May 1. Legere will remain on the board and said he wants to guide the Sprint merger to completion and help with the transition to the “New T-Mobile.”