The Arizona Court of Appeals on Tuesday revived a lawsuit challenging Gov. Jan Brewer's expansion of the state's Medicaid insurance plan for the poor, ruling that Republican lawmakers have the right to sue over their contention that a hospital assessment that funds the expansion is a tax requiring a two-thirds vote of the Legislature.

Republicans in the House and Senate sued last year, saying only a simple majority last June passed the expansion bill that included the assessment. A Maricopa County judge in February dismissed the case, saying lawmakers were suing over a lost political battle because the Legislature itself decides whether a supermajority vote is needed.

But the appeals court rejected that decision and sent the case back to Judge Katherine Cooper for more action. In an 11-page ruling, the unanimous three-judge panel said the 36 Republican lawmakers who sued could have defeated House Bill 2010 if the supermajority vote was required, so it was proper for Cooper to decide if the Arizona Constitution required that vote.

The ruling was a major loss for Brewer, who pushed the Medicaid bill through the Legislature by cobbling together a coalition of minority Democrats and 14 Republicans.

She is one of only a handful of Republican governors who embraced Medicaid expansion, a key part of President Barack Obama's health care law. In all, 25 states plus Washington, D.C., are moving ahead with the expansion, while 19 states have turned it down. An additional six states are weighing options.