By Terry Baynes

WASHINGTON (Reuters) - The U.S. Supreme Court on Wednesday considered whether U.S. courts of appeal have the authority to resolve an international custody dispute over a child who already has left U.S. soil with one parent under a court order.

It is not often the high court steps into a child custody battle, but the case turns on an international treaty, joined by more than 80 countries, that protects children from being abducted to other countries.

The case could affect many U.S. military personnel who are stationed around the globe and separated from children they had with non-U.S. nationals.

The nine justices heard arguments in the case of Jeffrey Chafin, a U.S. Army sergeant who is challenging a lower court ruling that awarded custody of his now 5-year-old daughter to her mother in Scotland under the Hague Convention on the Civil Aspects of International Child Abduction.

Lynne Chafin, a Scottish national, had lived with her daughter in Scotland since 2007, apart from her husband because of his job, according to court papers. In February 2010, she traveled with her daughter to visit him in Madison, Alabama, in a failed effort to save their marriage.

After divorce proceedings began, Lynne Chafin was deported to Scotland after overstaying her visa, and she sued under the treaty to obtain her daughter's return to Scotland.

A federal judge in Alabama ruled in October 2011 that the mother could take her daughter to Scotland, calling it the child's "habitual residence" under the Hague Convention. Within hours of the court's order, the mother and daughter were on a flight to Scotland.

Jeffrey Chafin sought to have the district court's ruling overturned, but the 11th U.S. Circuit Court of Appeals in February dismissed his appeal, saying the issue was moot because the girl by then was already in Scotland and beyond the court's control.

HOME FREE?

On Wednesday, several justices expressed concern that finding the U.S. appeal moot would encourage parents to flee to other countries with their children immediately after winning in the lower court.

"Get on the first plane out and then you're home free. That seems to me to be a very unfortunate result," said Chief Justice John Roberts.

Stephen Cullen, a lawyer for Lynne Chafin, responded that the point of the treaty was to give one country control over the case to prevent children from being shuttled back and forth. The United States signed onto the treaty because it trusted other member countries to "do the right thing," he said.

Lynne Chafin has since filed for custody in Scotland, and she contends that U.S. courts have no power to bring the child back to the United States. Continued...