In Phillips v. Ford, Judge Posner framed the issue as follows: “‘A routine amendment to the complaint does not commence a new suit.’ But is adding a plaintiff to a class action suit ‘routine’?  We said in Schorsch that ‘a defendant added after [CAFA’s effective date] could remove because suit against it would have been commenced after the effective date, and tacking a wholly distinct claim for relief onto an old suit likewise might commence a new proceeding.’ An amendment that merely changed the definition of and hence membership in the class was ‘routine,’ but we noted that the suit remained one between the original parties. No named plaintiffs had been added; the alteration of the class had added just new, unnamed class members.” Because, the Court concluded, “Illinois in effect allows named plaintiffs to be substituted with relation back (‘in effect’ because the formal rule is that the filing of a class action tolls the statute of limitations for class members, so that they can if necessary be substituted for the named plaintiffs, without being barred by reason of the passage of time since the suit was filed), the addition of such plaintiffs in the two cases before us did not commence new suits.” In Knudsen v. Liberty Mutual, however, a different panel, in a decision authored by Judge Easterbrook, concludes that a new action is ‘commenced’ under CAFA when simply a ‘novel’ claim is added against the same defendant or defendants. In that case, Plaintiffs alleged that Liberty Mutual paid too little on claims for medical services under workers’ compensation and casualty policies. All three plaintiffs were covered by Liberty Mutual Fire Insurance Company; but the suit named only its corporate parent, Liberty Mutual Insurance Company. After an unsuccessful removal, the plaintiffs asked the state court to hold Liberty Mutual responsible for all policies issued by any subsidiary or affiliate. When a nationwide class was certified, Liberty Mutual removed again. The Court acknowledged that, under Illinois law, a new contention relates back to the original complaint (and hence is not a new ‘claim for relief’ or ’cause of action’) when the original pleading furnishes the defendant with notice of the events that underlie the new contention. However, because the original complaint did not put Liberty Mutual on notice that it was going to be responsible as alter ego for the conduct of its affiliates and subsidiaries, it was a ‘new’ claim ‘commenced’ after CAFA’s effective date. Compare Phillips v. Ford Motor Co., 435 F.3d 785 (7th Cir. 2006); with, Knudsen v. Liberty Mutual Insurance Co.,435 F.3d 755 (7th Cir. 2006).

[See also: Pubell v. Merck, 434 F.3d 1070 (8th Cir. 2006) (addition of named plaintiff falling within original class definition ‘related back’ under State Law and was therefore ‘commenced’ prior to CAFA); and Braud v. Transport Service Company of Illinois, 445 F.3d 801 (5th Cir. 2006).]