Jackson, J., dissenting
compel arbitration. Griggs merely prevents the district court from modifying that order—i.e., Griggs prevents the district judge from revisiting whether to compel arbitration while the appeal is pending. Griggs does not stop the district court from proceeding on matters other than arbitrability.
The majority opinion, however, transmogrifies Griggs into a sweeping stay of “pre-trial and trial proceedings” on not just arbitrability, but also the merits. Ante, at 1. According to the majority, if the question on appeal is “whether the litigation may go forward in the district court,” then the district court loses control over “the entire case.” Ante, at 3–4 (emphasis added; internal quotation marks omitted).
That rule far surpasses the statement in Griggs—the sole statement on which the majority relies—that a district court loses “control over those aspects of the case involved in the appeal.” 459 U. S., at 58; ante, at 3. Only the arbitrability order is on appeal, not the merits. And those matters are distinct. As this Court recognized (before Congress enacted §16), “arbitrability” is “easily severable from the merits of the underlying disputes.” Moses H. Cone Memorial Hospital v. Mercury Constr. Corp., 460 U. S. 1, 21 (1983).
The majority cannot justify why it treats these “easily severable” matters as intertwined in an arbitrability appeal. “[T]he question on appeal,” as the majority opinion correctly identifies, is “whether the case belongs in arbitration.” Ante, at 3. But the questions remaining before the district court are different: whether the claims have merit, whether the parties are entitled to the discovery they seek, and so on. Proceedings on those questions would not interfere with the appellate court’s review of the arbitrability order. Those proceedings, in other words, do not implicate the Griggs principle, which addresses the “danger a district
