Too often, the gravitational pull of the venerable Erie doctrine draws state courts into filling state law lacuna with doctrines ^,”promulgated” by federal courts. In this Article, Lowenthal and Feder argue that Erie does not require state courts to embrace the rulings of their federal counterparts, although state courts may choose to do so. Focusing on the class action tolling doctrine de- vised by the Supreme Court in American Pipe and that doctrine’s application to mass tort litigation—which almost always comprises state law claims—the Authors demonstrate that, although commonly assumed otherwise, the federal class action tolling doctrine is not state law simply because of its provenance. If it does anything, Erie prohibits federal court meddling in substantive state law and, under either the Rules Enabling Act or the Rules of Decision Act, an automatic extension of American Pipe to state law claims constitutes exactly that kind of meddling.

State courts addressing mass torts should independently examine the worth of class action tolling and, the Authors argue, not admit it to the state canon. In mass torts, it is difficult to square the American Pipe doctrine with its stated goal of litigative economy; indeed, class action tolling may well generate more litigation than its saves. Moreover, under American Pipe’s own requirement that, to trigger tolling, the class action notify defendants of the individual claims and claimants they ultimately may face so that the defend- ants can gather the evidence they will need to defend themselves in any related individual litigation, class action tolling cannot properly apply to mass tort actions. Thus, not only does class action tolling for mass torts make poor state law, federal courts hearing state law claims must look to state law—not to American Pipe and its progeny—to determine the extent of class action tolling, if any.