This bill amends the Endangered Species Act of 1973 to revise provisions governing citizen suits against the Department of the Interior or the Department of Commerce, as appropriate, that allege a failure of the relevant department to perform an act or duty related to an endangered species or threatened species. Interior must publish the complaint in a citizen suit within 30 days of being served. Affected parties shall be given a reasonable opportunity to intervene in the suit. If affected parties intervene, the court must refer the action to a mediation program or magistrate judge to facilitate settlement discussions. The court is prohibited from: (1) awarding litigation costs in a citizen suit that is settled by a consent decree, or (2) awarding litigation costs to a plaintiff in a citizen suit that is settled. Interior must provide notice of a proposed settlement to each state or county in which an affected species occurs. A settlement can only be approved if states or counties approve the settlement or fail to respond.