Page:Lamps Plus, Inc. v. Frank Varela.pdf/47

12, Commentaries on the Laws of England 380 (1766) (anticipating that view by 200-plus years). And from an ex post perspective, the rule enables an interpreter to resolve any remaining uncertainty in line with the parties’ likely expectations. See 11 Williston §30:1, at 11. Consider this very contract. Lamps Plus, knowing about the anti-drafter rule, still chose not to include a term prohibiting class arbitration. And Varela, seeing only the language sending “any and all disputes, claims, or controversies” to arbitration, had no reason to think class disputes barred. Cf. ibid. (“[T]he party addressed will understand ambiguous language in the sense most favorable to itself”). The upshot is that the rule (as this Court recognized in another arbitration case) protects against “unintended” consequences. Mastrobuono, 514 U. S., at 63.

And even if that were not so evident, the FAA does not empower a court to halt the operation of such a garden-variety principle of state law. Nothing in the Act’s text requires the displacement of state contract rules, as the majority implicitly concedes. See ante, at 6. Nor do the Act’s purposes, so long as the state rule (as is true here) extends to all contracts alike, without disfavoring arbitration. See supra, at 6–7. The idea that the FAA blocks a state rule satisfying that standard because (a court finds) the rule has too much “public policy” in it comes only from the majority’s collective mind. That approach disrespects the preeminent role of the States in designing and enforcing contract rules. It discards a universally accepted principle of contract interpretation in favor of unsupported assertions about what the parties must have (or could not possibly have) consented to. It subordinates authoritative state law to (at most) the impalpable emanations of federal policy, impossible to see except in just the right light. For