PHOENIX (AP) - The Arizona Supreme Court has upheld a hospital assessment that helps pay for Medicaid insurance for 400,000 low-income Arizonans.

The high court ruled Friday on a challenge brought by Republican lawmakers who opposed the Medicaid expansion plan championed by former Gov. Jan Brewer in 2013.

Losing the assessment could have forced major enrollment cuts.

The lawmakers' lawyers argued that the hospital assessment is actually a tax that required a two-thirds vote under a voter-approved 1992 Constitutional amendment.

Brewer only got a majority of lawmakers to back the plan.

The state's Medicaid agency and a group representing Medicaid recipients argued an exemption for fees set by state agencies means the hospital assessment is legal. Lower courts agreed with that argument.