The legal precedent: One of the cases that may be key in future arguments over limiting access to the pills involves a lawsuit over a painkiller. In 2014, Massachusetts instituted an emergency ban on the opioid Zohydro, saying the drug was dangerous and addictive.

But a federal judge struck down the ban, saying a state couldn’t take a drug off the market that the FDA had deemed safe, Rachel Rebouché, interim dean of Temple University’s law school, tells Axios.

Experts might argue that means states don’t have the authority to ban FDA-approved drugs, including abortion drugs. Some might even go so far as to argue that the FDA’s policies would preempt any attempt by states to ban abortion, Rebouché said.

“That’s a stretch,” she says. “I think a lot of people think that’s a difficult argument to make because states for so long have been able to regulate the practice of medicine and a law that says you can’t perform an abortion seems like regulating the practice of medicine.”