The dissent is displeased with our decision on this score, but a contradiction lies at the heart of its critique. First, the dissent assures us that the immovable property exception applies with irresistible force—nothing more than a matter of “hornbook law.” Post, at 3–10 (opinion of THOMAS, J.). But then, the dissent claims that allowing the Washington Supreme Court to address that exception is a “grave” decision that “casts uncertainty” over the law and leaves lower courts with insufficient “guidance.” Post, at 3, 13–14. Both cannot be true. If the immovable property exception presents such an easy question, then it’s hard to see what terrible things could happen if we allow state court colleagues are no less versed than we in “hornbook law,” and we are confident they can and will faithfully apply it. And what if, instead, the question turns out to be more complicated than the dissent promises? In that case the virtues of inviting full adversarial testing will have proved themselves once again. Either way, we remain sanguine about the consequences.