The Texas Supreme Court heard oral arguments Wednesday in a closely watched case by family law attorneys and public policy groups.

Constitutional rights of parents are at play in the child-custody dispute between a father and the former fiancé of a mother who died in a car accident.

The appeal raises questions about when and how heavily courts should consider parental rights during disputes, where a nonparent is seeking possession of, or access to, a child.

The case also makes distinctions between the proper legal standards for courts to weigh in original child custody lawsuits, versus suits to modify child custody arrangements.

The case has attracted 10 amicus briefs from groups such as the State Bar of Texas Family Law Section's council, the newly-formed advocacy group Texas Association of Family Defense Attorneys, the conservative-leaning think tank the Texas Public Policy Foundation, and even the state of Texas itself.

In this case, the child's mother filed a lawsuit before her death to modify her child-custody agreement with the father. After her death, the father sought sole custody of the girl.

But the deceased mother's fiancé, a man who had lived with the mother and child for 10 or 11 months, intervened and sought some possession of, or access to the child. A trial court entered a temporary order that allowed the fiancé to see the child for two days per month and granted some other rights.

The dispute reached the Supreme Court when the father filed a petition for writ of mandamus, which the fiancé is fighting.

Father's arguments

The father argues that the trial court's temporary order violated his constitutional rights under U.S. Supreme Court case law in 2000′s Troxel v. Granville. The case held that a fit parent can determine how to care for his own child free from state interference.

The father argued in his brief on the merits that the fiancé used a Texas statute and a 2018 Texas Supreme Court ruling, In Re H.S., to gain standing in the case. He's asking the high court to clarify that even if someone has standing in a modification suit, it doesn't mean courts may disregard the fit-parent presumption.

"An opinion from this court is vitally important to ensure all fit parents in Texas have their constitutional rights protected in light of the generous standing awarded to non-parents by statutes not requiring a showing of significant impairment," the father's brief said.

The father's attorney, Holly Draper, told the Supreme Court during Wednesday's oral arguments, which were held remotely through video conference, that it was easier for the fiancé to gain standing in the custody dispute than it is for grandparents or other relatives.

Fiancé's position

On the other side, the fiancé argues that Texas statutes and Texas Supreme Court precedent spanning back to 1955 from have established that in child custody modification lawsuits, the parental presumption doesn't apply.

He argues that instead, trial courts are supposed to determine if there have been any material and substantial changes in circumstances, and they're supposed to keep the best interest of the child in mind.

The fiancé claims in his brief on the merits that in this case, the trial court followed well-established law, and it did not abuse its discretion when it entered the temporary orders. Mandamus is not an available remedy for the father, the fiancé argues.

According to his brief, there is a constitutional right for a parent to raise a child without state interference. But in this case, the father specifically went to the courts for help determining child custody. That meant he waived the parental presumption in later modification proceedings, claimed the fiancé.

Arguing for him, attorney Michelle O'Neil said that the deceased mother made the decision to bring the fiancé into the child's life.

"She called him 'Pops,' " O'Neil said. " In his heart and in the child's heart, they felt he was a parent-like figure."

She argued that a trial court has to consider many competing factors to decide what's best for a child in a custody case, and that only one of those factors is the presumption that a fit parent acts in the child's best interests. It would be wrong to prioritize parental rights over the child's rights, she said.