Breyer, J., dissenting
tory appeals will too often unnecessarily delay proceedings while a party appeals and loses. And delays can clog the appellate system, thereby slowing down the workings, and adding to the costs, of the judicial system seen as a whole. Congress’ jurisdictional statutes consequently compromise, providing, for example, for interlocutory appeals in some instances, such as cases involving injunctive orders, see, e. g., 28 U. S. C. §1292(a)(1), or where important separable legal questions are at issue, see, e. g., Ashcroft v. Iqbal, 556 U. S. 662, 671 (2009), or where a district court certifies an open legal question to a court of appeals for determination, see, e. g., 28 U. S. C. §1292(b). But often statutes and rules require the parties to proceed to the end of a trial before obtaining appellate review. See, e. g., §1291.
The statutory provisions before us are a local species of this jurisdictional genus. In them, Congress limited interlocutory review of orders concerning arbitration in a way that favors arbitration. Consequently, §16(a) of the FAA will normally allow an immediate appeal where arbitration is denied, but §16(b) will normally require parties to wait until the end of the arbitration in order to bring legal questions about that proceeding to a court of appeals.
A couple of examples illustrate the point. Take first §4 of the FAA. Section 4 provides that a “court,” upon being satisfied that the parties have agreed to arbitrate a claim, “shall make an order directing the parties to proceed to arbitration in accordance with the terms of the agreement.” 9 U. S. C. §4. Section 16(a) of the FAA provides that a party may immediately appeal a district court order refusing to compel arbitration under §4, while §16(b) provides that a party generally may not immediately appeal a district court order compelling arbitration under §4. Compare §16(a)(1)(B) (“An appeal may be taken from” an order “denying a petition under section 4 of this title”) with §16(b)(2) (“[A]n appeal may not be taken from an
