The ongoing debate over the proposed development of a third casino in East Windsor, Connecticut, has taken a new twist this week. MGM Resorts has filed a lawsuit challenging federal approval of the joint venture between the Mashantucket Pequot and Mohegan tribes which would create competition for its own Springfield casino, located less than 20 miles away.

News of the lawsuit came after Connecticut Governor Ned Lamont had met with resistance from the Mashantucket Pequot and Mohegan tribes to his proposal that they reconsider their plans for the new casino. 

He had requested that they shelve the project, which is being undertaken by the tribes’ joint venture MMCT, in exchange for legalized sports betting statewide, a Bridgeport casino and the opportunity to renovate and add gambling to the XL Center in Hartford. 

The lawsuit, which was filed Wednesday in Washington, challenges the Department of the Interior’s approval of amendments to the established gaming compact between the state and the Mashantucket Pequot and Mohegan tribes.

In support of the lawsuit, MGM argued that federal approval creates an unlawful advantage for the tribes in competing for casino rights outside of tribal boundaries. To compound matters, the company is also competing with the tribes for the rights to open a casino in Bridgeport.

Both tribes have yet to issue a formal response to MGM’s legal move, but with nearly $20m invested in the Tribal Winds development, it is unlikely they will relinquish their interest without a fight.