(a) In general

(1) Civil actions
In any case in which the attorney general of a State has reason to believe that an interest of the residents of that State has been or is threatened or adversely affected by the engagement of any person in a practice that violates any regulation of the Commission prescribed under section 6502(b) of this title, the State, as parens patriae, may bring a civil action on behalf of the residents of the State in a district court of the United States of appropriate jurisdiction to—

(A) enjoin that practice;

(B) enforce compliance with the regulation;

(C) obtain damage, restitution, or other compensation on behalf of residents of the State; or

(D) obtain such other relief as the court may consider to be appropriate.

(2) Notice

(A) In general
Before filing an action under paragraph (1), the attorney general of the State involved shall provide to the Commission—

(i) written notice of that action; and

(ii) a copy of the complaint for that action.

(B) Exemption

(i) In general
Subparagraph (A) shall not apply with respect to the filing of an action by an attorney general of a State under this subsection, if the attorney general determines that it is not feasible to provide the notice described in that subparagraph before the filing of the action.

(ii) Notification
In an action described in clause (i), the attorney general of a State shall provide notice and a copy of the complaint to the Commission at the same time as the attorney general files the action.

(b) Intervention

(1) In general
On receiving notice under subsection (a)(2), the Commission shall have the right to intervene in the action that is the subject of the notice.

(2) Effect of intervention
If the Commission intervenes in an action under subsection (a), it shall have the right—

(A) to be heard with respect to any matter that arises in that action; and

(B) to file a petition for appeal.

(3) Amicus curiae
Upon application to the court, a person whose self-regulatory guidelines have been approved by the Commission and are relied upon as a defense by any defendant to a proceeding under this section may file amicus curiae in that proceeding.

(c) Construction
For purposes of bringing any civil action under subsection (a), nothing in this chapter shall be construed to prevent an attorney general of a State from exercising the powers conferred on the attorney general by the laws of that State to—

(1) conduct investigations;

(2) administer oaths or affirmations; or

(3) compel the attendance of witnesses or the production of documentary and other evidence.

(d) Actions by Commission
In any case in which an action is instituted by or on behalf of the Commission for violation of any regulation prescribed under section 6502 of this title, no State may, during the pendency of that action, institute an action under subsection (a) against any defendant named in the complaint in that action for violation of that regulation.

(e) Venue; service of process

(1) Venue
Any action brought under subsection (a) may be brought in the district court of the United States that meets applicable requirements relating to venue under section 1391 of title 28.

(2) Service of process
In an action brought under subsection (a), process may be served in any district in which the defendant—

(A) is an inhabitant; or

(B) may be found.