Iowa constitution
Article III
Section 36

Upon verified application by any qualified elector, the supreme court shall review an apportionment plan adopted by the general assembly which has been enacted into law. Should the supreme court determine such plan does not comply with the requirements of the constitution, the court shall within ninety days adopt or cause to be adopted an apportionment plan which shall so comply. The supreme court shall have original jurisdiction of all litigation questioning the apportionment of the general assembly or any apportionment plan adopted by the general assembly.