An emerging issue for attorneys involved in complex litigation is whether parens patriae lawsuits brought by a state attorney general can be construed as mass actions or class actions subject to federal diversity jurisdiction under the Class Action Fairness Act of 2005 ("CAFA").

The parens patriae doctrine, rooted in English common law, grants states standing to sue in order to protect the interests of their citizens.  Initially quite limited, the doctrine has been expanded over the last half-century to permit state attorneys general to bring suit anytime they can establish a "quasi-sovereign" interest, such as an interest in the physical and economic health and well-being of its residents.  SeeAlfred L. Snapp& Sons v. Puerto Rico ex rel. Barez, 458 U.S. 592, 593 (1982).  Indeed, many states have enacted laws expressly authorizing its state's attorney general to bring parens patriae suits, especially in the context of antitrust and consumer protection violations.