When the Attorney General issues a written opinion that an act of the Legislature is unconstitutional and any state officer charged with the duty of implementing the act, in reliance on such opinion, refuses to implement the act, the Attorney General shall, within ten working days of the issuance of the opinion, file an action in the appropriate court to determine the validity of the act. In any such action filed under the provisions of this section, the Attorney General may sue as defendant any person having a litigable interest in the matter or in lieu thereof may sue the Secretary of State. If the Secretary of State is named as defendant, it shall be his duty to defend such action and to support the constitutionality of the act of the Legislature and for such purpose is authorized to employ special counsel. Notwithstanding the provisions of this section, no such action need be brought by the Attorney General if there is pending in any court of the state a legal action for the purpose of testing the constitutionality of the act. Any person having a litigable interest may be joined in the action or may intervene in the action, but shall not be deemed a necessary party in order to determine the validity of the act.