By Jonah Knobler (July 14, 2017, 11:49 AM EDT) -- On July 7, 2017, in In re Petrobras Securities, the Second Circuit fired the latest salvo in the class action ascertainability wars. In Petrobras, the panel purported to "clarify" the Second Circuit's leading ascertainability decision, Brecher v. Republic of Argentina, 806 F.3d 22 (2015). In reality, however, it essentially rewrote Brecher, stretching it beyond recognition to revamp the Second Circuit's law of ascertainability. The impact of Petrobras remains to be seen; indeed, its whole discussion of ascertainability is technically just dicta. One thing is for sure, however: it does little to make things "clearer" for litigants or lower courts....