LITTLE ROCK, Ark. (AP) — Cherokee Nation Entertainment filed a lawsuit Friday challenging a constitutional amendment approved by Arkansas voters this week that revokes its license for a planned casino in the state.

The lawsuit filed in federal court challenges the measure approved by voters on Tuesday is infringing on his constitutional rights and trying to block its implementation before it takes effect on November 13. Constitutional amendment block a casino that was planned in Pope County.

Pope County was one of four sites where casinos were allowed to be built under a constitutional amendment that voters approved in 2018. Casinos have already been established in the other three locations.

“Cherokee Nation Entertainment is firmly committed to protecting its constitutional rights, defending its lawfully issued casino license, and protecting the substantial investments it has made in good faith in establishing the Pope County casino license in pursuant to the 100th Amendment of 2018,” Bart Calhoun, an attorney for Cherokee Nation Entertainment, said in a statement.

The lawsuit is the latest in a costly battle between the Cherokee Nation and the Choctaw Nation of Oklahoma, which had spent at least $30 million campaigning for the ballot measure. The state Supreme Court last month rejected a lawsuit by the Cherokee Nation that sought to disqualify the measure from the ballot. The Choctaw Nation operates a casino near the Arkansas border.

“This legal action to try to circumvent the voice of Arkansas voters is not unexpected,” said Hans Stiritz, a spokesman for Local Voters in Charge, the Choctaw Nation-backed campaign in favor of the measure. “But we have full confidence in the process that brought No. 2 to the vote. Arkansas voters have spoken clearly on No. 2, and we expect it to stand.”

Attorney General Tim Griffin called the lawsuit “baseless” and said he was prepared to vigorously defend the state.

The proposed amendment removes Pope County’s casino authorization from the state constitution. It also requires that future casino licenses be approved by voters in the county where they would be located. Currently, the constitution requires applicants for casino licenses to submit letters of support from local officials.

Cherokee Nation Entertainment said it plans to build a 50,000-square-foot (4,600 square meter) casino northeast of Russellville, 60 miles (97 kilometers) northwest of Little Rock. Plans also call for a 200-room hotel, a conference center and an outdoor music venue.