The second circuit recently resolved the issue of whether a plaintiff can maintain a class action under the Telephone Consumer Protection Act where a class action is not authorized under state law.  Answer:  no.  (Access the opinion here [pdf].) 

The TCPA is an odd statute.  It's a federal statute (which regulates unsolicited fax as well as certain calls) that provides for exclusive jurisdiction in state courts.  Only to the extent "otherwise permitted by" the rules or statutes of the state.  (Here's an article on Congressional power over state courts.)  TCPA lawsuits are allowed in NY state courts, but not on a class action basis.  I guess there's a New York rule which says that class actions can only be brought where expressly authorized. 

To try to get around this, plaintiff sued in federal court under the Class Action Fairness Act (which shifts certain class actions to federal court).  The question was whether he could maintain a class action this way and get around the New York state procedural rule.

Those who are truly curious should read the opinion rather than my summary, but a few arguments swayed the court.  First, allowing class actions would spur forum shopping.  Second, Congress indicated that courts should treat the TCPA as if it were state law and state (rather than federal) procedural rules should apply (I didn't quite digest this argument completely - the concurring judge notes that since the right at issue arises under federal law, Erie does not apply).

The concurring judge Calabresi cuts through the needlessly complicated reasoning employed by the other two judges on the panel and looks to the text of the TCPA.  According to him, the text makes clear that lawsuits can be maintained only to the extent authorized under the rules of the applicable state, which is not the case here - end of story.

The TCPA is a strange animal.