2. Defendant’s pleading of a federal affirmative defense to a state law claim generally does not support removal. An important but complex exception involves the doctrine of complete preemption, when state claims are so exclusively federal in nature as to extinguish any state cause of action and to render the claim entirely federal. As the Supreme Court has explained, “[I]f a federal cause of action completely preempts a state cause of action any complaint that comes within the scope of the federal cause of action necessarily ‘arises under’

federal law.” Francise Tax Bd. of State of California v. Construction Laborers Vacation Trust for Southern California, 463 U.S. 1, 23-24, 103 S.Ct. 2841, 2853-54, 77 L.Ed.2d 420, 440

(1983). Is this doctrine consistent with Mottley’s well-pleaded complaint rule or an exception to it?