Opinion of the Court
engaged in foreign or interstate commerce.” Why this very particular qualification? By the time it adopted the Arbitration Act in 1925, Congress had already prescribed alternative employment dispute resolution regimes for many transportation workers. And it seems Congress “did not wish to unsettle” those arrangements in favor of whatever arbitration procedures the parties’ private contracts might happen to contemplate. Circuit City Stores, Inc. v. Adams, 532 U. S. 105, 121 (2001).
Given the statute’s terms and sequencing, we agree with the First Circuit that a court should decide for itself whether §1’s “contracts of employment” exclusion applies before ordering arbitration. After all, to invoke its statutory powers under §§3 and 4 to stay litigation and compel arbitration according to a contract’s terms, a court must first know whether the contract itself falls within or beyond the boundaries of §§1 and 2. The parties’ private agreement may be crystal clear and require arbitration of every question under the sun, but that does not necessarily mean the Act authorizes a court to stay litigation and send the parties to an arbitral forum.
Nothing in our holding on this score should come as a surprise. We’ve long stressed the significance of the statute’s sequencing. In Bernhardt v. Polygraphic Co. of America, 350 U. S. 198, 201–202 (1956), we recognized that “Sections 1, 2, and 3 [and 4] are integral parts of a whole…. [Sections] 1 and 2 define the field in which Congress was legislating,” and §§3 and 4 apply only to contracts covered by those provisions. In Circuit City, we acknowledged that “Section 1 exempts from the [Act]… contracts of employment of transportation workers.” 532 U. S., at 119. And in Southland Corp. v. Keating, 465 U. S. 1, 10–11, and n. 5 (1984), we noted that “the enforceability of arbitration provisions” under §§3 and 4 depends on whether those provisions are “part of a written maritime contract or a contract ‘evidencing a transaction in-
