N.Y. Executive Law § 71

           N.Y. Executive Law § 71.  Attorney-general  authorized  to  appear  in cases involving the  constitutionality of an act of the legislature, or a rule or  regulation adopted  pursuant  thereto. 

1.  Whenever  the  constitutionality  of  a  statute, or a rule or regulation adopted  pursuant  thereto  is  brought   into  question  upon  the  trial,  hearing  or appeal  of any action or  proceeding, civil or criminal, in any court of  record  of  original  or  appellate  jurisdiction,  and proof of the notice of such constitutional challenge, as required by paragraph one of subdivision  (b)  of  section one  thousand  twelve  of the civil practice law and rules, has not been filed, the court or justice before whom such  action  or  proceeding  is pending, shall make an order, directing the party desiring to raise such question, to serve notice thereof on the attorney-general, and providing that  the attorney-general  be permitted to appear at any such trial or hearing in support of the constitutionality of such statute, or rule or regulation adopted  pursuant  thereto. The court or justice before whom any such action or proceeding is pending may also make such  order  upon the  application  of  any  party  thereto, and the court shall make such order  in  any  such  action  or   proceeding   upon   motion   of   the attorney-general.  When such order has been made in any manner mentioned in this section and notice pursuant to such order has  been  given,  the attorney-general  shall  be  permitted  to  appear  in  such  action  or proceeding in support of the constitutionality of  such  statute,  or  a rule or regulation adopted pursuant thereto.

2.   In  the  event  the  constitutionality of a statute, or rule or regulation adopted pursuant thereto is brought into question and the party  questioning  such  constitutionality,  or  any other party to the action or proceeding serves the attorney-general pursuant  to  paragraph one  of  subdivision  (b)  of  section  one thousand twelve of the civil practice law and rules, proof of such service upon the  attorney-general shall  be  accepted  by  the  court in satisfaction of the provisions of subdivision one of this section.

3.   The court having jurisdiction in an action or proceeding  in  which the  constitutionality  of  a statute, rule or regulation is challenged, shall not consider  any  challenge  to  the  constitutionality  of  such statute,  rule  or  regulation  unless  proof  of  service of the notice required by this section or required by subdivision (b) of  section  one thousand  twelve  of the civil practice law and rules is filed with such court.

N.Y. C.P.L.R. 1012. Intervention as of right; notice to attorney-general, city, county, town or village where constitutionality in issue

(a)  Intervention as of right. [Omitted]

(b)  Notice to attorney-general, city, county, town or village where constitutionality in issue.

1.   When the constitutionality of a statute of the state, or a rule and regulation adopted pursuant thereto is involved in an action to which the state is not a party, the attorney-general, shall be notified and permitted to intervene in support of its constitutionality.

2.   When the constitutionality of a local law, ordinance, rule or regulation of a city, county, town or village is involved in an action to which the city, county, town or village that enacted the provision is not a party, such city, county, town or village shall be notified and permitted to intervene in support of its constitutionality.

3.   The court having jurisdiction in an action or proceeding in which the constitutionality of a state statute, local law, ordinance, rule or regulation is challenged shall not consider any challenge to the constitutionality of such state statute, local law, ordinance, rule or regulation unless proof of service of the notice required by this subdivision is filed with such court.

(c)  Notice to comptroller of the state of New York where public retirement benefits are in issue. [Omitted]

 

N.Y. Court of Appeals Rules of Practice
22 N.Y.C.R.R. § 500.9.  Preliminary Appeal Statement.
             
(a)  Within 10 days after an appeal is taken by (1) filing a notice of appeal in the place and manner required by CPLR 5515, (2) entry of an order granting a motion for leave to appeal in a civil case, or (3) issuance of a certificate granting leave to appeal in a noncapital criminal case, appellant shall file with the clerk of the Court an original and one copy of a preliminary appeal statement on the form prescribed by the Court, with the required attachments and proof of service of one copy on each other party. No fee is required at the time of filing the preliminary appeal statement.
       
(b)  Where a party asserts that a statute is unconstitutional, appellant shall give written notice to the Attorney General before filing the preliminary appeal statement, and a copy of the notification shall be attached to the preliminary appeal statement. The notification and a copy of the preliminary appeal statement shall be sent to the Solicitor General, Department of Law, The Capitol, Albany, New York 12224.
       
(c)  After review of the Preliminary Appeal Statement, the clerk will notify the parties either that review pursuant to section 500.10 or section 500.11 of this Part shall commence or that the appeal shall proceed in the normal course.
42 U.S.C. § 2403.  Intervention by United States or a State; constitutional question

(a)  [Omitted ― Governing notice to the United States]

(b) In any action, suit, or proceeding in a court of the United States to which a State or any agency, officer, or employee thereof is not a party, wherein the constitutionality of any statute of that State affecting the public interest is drawn in question, the court shall certify such fact to the attorney general of the State, and shall permit the State to intervene for presentation of evidence, if evidence is otherwise admissible in the case, and for argument on the question of constitutionality. The State shall, subject to the applicable provisions of law, have all the rights of a party and be subject to all liabilities of a party as to court costs to the extent necessary for a proper presentation of the facts and law relating to the question of constitutionality.

 

Federal Rules of Appellate Procedure, Rule 44.  Case Involving a Constitutional Question When the United States or the Relevant State is Not a Party

(a)  Constitutional Challenge to Federal Statute. [Omitted]

Federal Rule of Civil Procedure, Rule 24.  Intervention

(a) Intervention of Right. On timely motion, the court must permit anyone to intervene who:

(1)  is given an unconditional right to intervene by a federal statute; or

(2) claims an interest relating to the property or transaction that is the subject of the action, and is so situated that disposing of the action may as a practical matter impair or impede the movant's ability to protect its interest, unless existing parties adequately represent that interest.

(b) Permissive Intervention.

(1) In General. On timely motion, the court may permit anyone to intervene who:

(A) is given a conditional right to intervene by a federal statute; or

(B) has a claim or defense that shares with the main action a common question of law or fact.

(2) By a Government Officer or Agency. On timely motion, the court may permit a federal or state governmental officer or agency to intervene if a party's claim or defense is based on:

(A) a statute or executive order administered by the officer or agency; or

(B) any regulation, order, requirement, or agreement issued or made under the statute or executive order.

(3) Delay or Prejudice. In exercising its discretion, the court must consider whether the intervention will unduly delay or prejudice the adjudication of the original parties' rights.

(c) Notice and Pleading Required. A motion to intervene must be served on the parties as provided in Rule 5. The motion must state the grounds for intervention and be accompanied by a pleading that sets out the claim or defense for which intervention is sought.