In Hyman v. City of Gastonia the Fourth Circuit issued an interesting opinion on abatement. Hyman appealed the district court's application of North Carolina's doctrine of abatement, which resulted in the dismissal of Hyman's diversity action against the City of Gastonia. Under 28 USC 2105, "[t]here shall be no reversal" of an abatement ruling issued from a lower court. The panel interpreted this language to mean that the statute completely deprives an appellate court of authority to review a district court's abatement ruling.
Examples of abatement, according to the panel, include (1) a defense of prematurity, i.e., that the plaintiff commenced the lawsuit before the underlying cause of action accrued; (2) a defense that the plaintiff's interest in the pending lawsuit has terminated or transferred to another party; (3) a defense that a lawsuit cannot proceed because of the death of either the plaintiff or the defendant; and (4) a defense that there is a separate, identical lawsuit pending.
Hence, a favorable abatement ruling could be a powerful tool for a litigant to use.