This week, Indiana Attorney General Greg Zoeller filed a lawsuit against the Internal Revenue Service (IRS) challenging its authority to fund Obamacare’s insurance subsidies for individuals and enacting penalties against public employers (such as state and local governments) that don’t meet the health law’s minimum worker coverage requirement. If successful, the challenge would prevent Americans from receiving the government assistance that makes Obamacare’s insurance marketplace plans affordable in the first place.

Zoeller claims that the health law doesn’t permit people living in the 36 states that have refused to set up their own Obamacare marketplaces — including Indiana — to qualify for federal insurance subsidies. He also says that local government employers which don’t meet Obamacare’s requirements cannot be penalized under the law to help fund those subsidies.

The argument is based on a technical ambiguity in the law that state-level GOP officials and congressional Republicans have previously seized on in an attempt to undermine the ACA’s consumer assistance. The IRS has issued regulations saying that the law permits and intends the agency to extend subsidies to Americans in all 50 states.

More: Indiana Sues to Prevent Its Own Residents From Receiving Obamacare’s Insurance Subsidies