Arizona’s Supreme Court has agreed to hear arguments against former Gov. Jan Brewer’s adoption of statewide Medicaid expansion. 

The decision comes six months after the state court of appeals said Brewer’s 2013 plan of charging hospitals assessment fees was constitutional. That money helps insure more than 400,000 low-income Arizona residents.

But, attorney Adi Dynar with the conservative Goldwater Institute plans to argue that the assessment is a tax and is therefore unconstitutional. He represents GOP lawmakers who voted against the fee and claim, under Arizona state law passed in 1992, which requires any tax must have a two-thirds majority vote for approval.

“That’s the question that the Supreme Court will have to confront,” Dynar said on behalf of the GOP lawmakers. “Our position is it is a tax. It walks like a tax. It talks like a tax. It is a tax.”

If the Supreme Court ultimately rules in favor of the GOP lawmakers, the state would lose about $265 million annually, which helps pay for those who signed up for the coverage since it was expanded in 2013.