Filed in Washington D.C., MGM’s lawsuit is aimed at overturning the Department of the Interior’s approval of amendments to agreements between the state and Mashantucket Pequot and Mohegan tribes.

These amendments allow the tribes to share operations of a casino in East Windsor, 12 miles from MGM’s casino in Springfield, Massachusetts.

MGM’s representatives wrote in a statement: “The amendments are not limited to an East Windsor casino.  

“They facilitate commercial, off-reservation gaming by the tribal joint venture anywhere in Connecticut and state legislators have recently proposed granting the joint venture an exclusive, no-bid license to operate a casino in Bridgeport, Connecticut. The amendments thus confer a statewide, perpetual competitive advantage on the joint venture.”

Plans for the satellite casino in East Windsor were first discussed in 2014 when the two tribes saw it as a way to protect jobs at their Mohegan Sun and Foxwoods Resort Casino properties.

Leaders from the tribes are reported to have already invested roughly $14m into the East Windsor project; the site has been purchased and cleared, most state and local approvals have been obtained and an agreement has been reached with construction unions.

Connecticut’s compacts with the tribes gives them exclusive rights to certain verticals in exchange for 25% of slot machine revenue.