The Texas Supreme Court on Friday ruled that a trial court made a mistake by granting some child custody to the former fiance of the child's deceased mother although the child's father objected.

The family law bar was closely watching the case, In Re C.J.C., about the constitutional rights of parents in child-custody disputes because it raised questions about how courts should weigh parental rights in custody disputes where nonparents seek to modify custody orders.

"The question presented in this case is whether the presumption that fit parents act according to the best interest of their children applies when modifying an existing order that names a parent as the child's managing conservator," wrote Justice Jane Bland in the majority opinion. "Because a fit parent presumptively acts in the best interest of his or her child and has a 'fundamental right to make decisions concerning the care, custody, and control' of that child, we hold that it does."

The ruling is a huge win for Texas parents, said a statement by Holly Draper of The Draper Law Firm, who represented the biological father in the case.

"In finding that the trial court judge violated the father's constitutional rights when she awarded partial custody to a non-parent over the father's objections, the court has confirmed that the due process clause of the 14th Amendment protects the rights of a fit parent to parent a child without government interference," Draper said.

In this case, the child's mother filed a lawsuit to modify her child-custody agreement with the father. But the mother died in a car accident when the case was pending. After her death, the father sought sole custody of the girl.

But the deceased mother's fiance, 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 fiance to see the child for two days per month and granted some other rights.

The father filed a petition for writ of mandamus, which the fiance was fighting.

Read more: Lawyers Are Watching This Texas Child-Custody Dispute Before the High Court

The U.S. Supreme Court has ruled about the rights of parents, said the opinion. Texas law also recognizes the fundamental right.

Here, the child's father was a fit parent who loved and cared for the little girl, took her to counseling for her mother's death, helped her with school work at home and went to church together. He remarried a fifth-grade teacher since the mother's death, the opinion said.

When the trial court awarded the ex-fiance some custody, it was substituting its own judgment in place of the father's decision about what was in the child's best interest, the opinion said.

"The trial court's decision in the case reflects 'exactly the opposite' of a parental presumption," said the ruling.

Read the majority ruling

Although Texas law does not have the fit-parent presumption when it comes to custody modification proceedings, the Supreme Court concluded that courts must apply the presumption in any proceeding where a nonparent seeks custody.

The opinion added, "When a nonparent requests conservatorship or possession of a child, the child's best interest is embedded with the presumption that it is the fit parent—not a court—who makes the determination whether to allow that request."

Justice Debra Lehrmann in a concurring opinion discussed how courts should evaluate "whether the fit-parent presumption has been overcome in a particular case."

Read the concurring opinion