Andy and Anna Hershberger are appealing a court decision that allowed the guardian to step in. The Amish couple said they weren't objecting to the treatment for religious reasons but because they believe the chemotherapy was killing 11-year-old Sarah.
Meanwhile, the guardian says she can't contact the family and has asked to withdraw from the case.
The Hershbergers say assigning a guardian to have the final say robbed them of their constitutional rights. They're appealing under the Ohio Health Care Freedom Amendment that voters approved in 2011. The amendment prohibits any law from forcing Ohioans to participate in "a health care system."
Their appeal marks the first time a court has been asked to determine the scope of the amendment, which was largely thought to be a symbolic vote against President Barack Obama's health care overhaul.
Maurice Thompson of the libertarian 1851 Center for Constitutional Law in Ohio helped draft the state amendment and is now representing the Hershbergers.
"Allowing an uninterested third-party, one that has never even met the family or the child, to assert an interest in an exceedingly important parental decision will completely undermine the parent-child relationship," Thompson said in a filing with the Ohio Supreme Court.
Thompson also has filed an appeal in a state appeals court. In a filing with that court, he said that Ohio's guardianship statutes appear to let courts substitute their judgment for that of suitable parents and that the court should take a narrower view that limits such second-guessing and is consistent with constitutional safeguards of their rights.
Doctors say Sarah's leukemia is treatable, but she would die within a year without chemotherapy. Still, the Hershbergers decided last summer to halt the cancer treatments for Sarah because they said the chemo was making her too sick. Instead, they decided to use natural medicines, such as herbs and vitamins.
The hospital went to court to force the family to continue chemotherapy. A guardian, Maria Schimer, an attorney who's also a registered nurse, was given the power to make medical decisions for Sarah.
But the girl and her parents, who normally live in an Amish community about 40 miles southwest of Cleveland, went into hiding more than four months ago to avoid the chemotherapy. They don't plan to return to their farm until the guardian is removed, their attorney has said.
Schimer has since asked a judge to let her drop her attempt to force Sarah to resume chemotherapy because she can't contact the girl or her parents. A decision could come within several weeks.
While Schimer wants to step away, she also wants the ruling that allowed for a guardian to stand, arguing that the Hershbergers waited too long to claim that their constitutional rights had been violated.
Thompson, the Hershberger's attorney, called the case a significant constitutional issue under Ohio's health care amendment, which he said was designed to preserve "the right of parents and their children to choose their health care without compulsion and prevent forced health care."
Ohio voters in 2011 overwhelmingly approved the amendment prohibiting government from requiring Ohioans to buy health insurance. The measure, though, did not stop the implementation of Obama's new federal health care law because a state amendment can't nullify federal law.
Opponents of the amendment, including some liberal groups and legal experts, said during the campaign that the question's broad prohibitions against government intervention in the health care system could hurt Ohio's ability to enforce related state laws and regulations.
Marc Spindelman, a law professor who specializes in constitutional law at Ohio State University, said the question for the courts is whether the amendment can be stretched to apply to the Hershberger family's situation.
"It's not clear the health care amendment helps clarify the issue," he said. "It's not a slam dunk."