Opinion of the Court
dating classwide arbitration procedures without the parties’ consent.” Epic Systems, 584 U. S., at ___ (slip op., at 8). But that is precisely what the court below did, requiring class arbitration on the basis of a doctrine that “does not help to determine the meaning that the two parties gave to the words, or even the meaning that a reasonable person would have given to the language used.” 3 Corbin, Contracts §559, at 269–270. Such an approach is flatly inconsistent with “the foundational FAA principle that arbitration is a matter of consent.” Stolt-Nielsen, 559 U. S., at 684.
Varela and Justice Kagan defend application of the rule on the basis that it is nondiscriminatory. It does not conflict with the FAA, they argue, because it is a neutral rule that gives equal treatment to arbitration agreements and other contracts alike. See Brief for Respondent 18, 25–26; post, at 6–9 (Kagan, J., dissenting). We have explained, however, that such an equal treatment principle cannot save from preemption general rules “that target arbitration either by name or by more subtle methods, such as by ‘interfer[ing] with fundamental attributes of arbitration.’” Epic Systems, 584 U. S., at ___ (slip op., at 7) (quoting Concepcion, 563 U. S., at 344).
That was the case in Concepcion. There, the Court considered the general contract defense of unconscionability, which had been interpreted by the state court to bar class action waivers in consumer contracts, whether in the litigation or arbitration context. See id., at 341–344. The general applicability of the rule did not save it from preemption under the FAA with respect to arbitration agreements, because it had the consequence of allowing any party to a consumer arbitration agreement to demand class proceedings “without the parties’ consent.” Epic Systems, 584 U. S., at ___ (slip op., at 8) (describing the “essential insight” of Concepcion). That, for the reasons we have explained, “interferes with fundamental attrib-
