Kansas Gov. Sam Brownback has vetoed a bill that would have extended the state’s health coverage for the poor under former President Barack Obama’s signature health care law.

The conservative Republican governor made the move Thursday. He explained that he thinks the expansion would fail to serve the truly needy and would burden the state with what he called “unrestrainable entitlement costs.”

The bill would have expanded Medicaid coverage to as many as 180,000 additional adults.

Legislators gave final approval to the measure Tuesday. It had strong bipartisan majorities in both chambers, but supporters were short of the two-thirds majorities necessary to override a veto. Nevertheless, they are expected to try.

Brownback has been a vocal critic of the 2010 Affordable Care Act, also known as “Obamacare,” and his action was expected.