DES MOINES, Iowa—Attorneys representing five Republican lawmakers have filed court documents asking the Iowa Supreme Court to overturn a Polk County judge, who struck down a state law banning same-sex marriage in August.

The Alliance Defense Fund, an Arizona-based anti-gay organization, filed a friend of the court brief Jan. 29 for Iowa state Reps. Dwayne Alons, Carmine Boal and Betty DeBoef and Iowa state Sens. Nancy Boettger and James Hahn.

The brief says Judge Robert Hanson abdicated his duty to be fair and neutral in considering a legal challenge to a 1998 state law filed by gay couples.