211 U.S. 149 (1908)
The Mottleys possessed a valid cause of action against the Louisville & Nashville Railroad.1 In satisfaction of this claim, and prior to June 29, 1906, the Mottleys accepted a contract from the railroad that provided for free transportation passes. This agreement was entered in good faith by the parties.2
Congress passed an act on June 29, 1906, codified at 34 Stat. 584, which regulated the giving of free passes and required that compensation for transportation match the filed tariffs. The statute forbade the giving of free passes or the collection of any different compensation for transportation of passengers than that specified in the tariff filed.3
Following the enactment of this statute, the Mottleys instituted suit in the Circuit Court of the United States by filing a bill that sought to compel performance of the contract. The railroad company demurred to the bill, thereby raising questions of law concerning the continuing validity of the pre-existing agreement.4
No diversity of citizenship existed between the parties.5 The case came to the Supreme Court by appeal from the Circuit Court after the demurrer was addressed below.6 Neither party questioned the jurisdiction of the lower court, but the Supreme Court examined the issue on its own motion.7
Whether the Circuit Court had jurisdiction of the cause as a suit arising under the Constitution and laws of the United States?8
A suit arises under the Constitution and laws of the United States only when the plaintiff’s statement of his own cause of action shows that it is based upon those laws or that Constitution. It is not enough that the plaintiff alleges some anticipated defense to his cause of action and asserts that the defense is invalidated by some provision of the Constitution of the United States.9
No. The Mottleys' bill in the Circuit Court sought to compel performance of their contract for free passes, which they had accepted before the 1906 statute in satisfaction of their valid cause of action against the railroad.10 The plaintiffs' statement of their cause of action does not rely on any federal law or constitutional provision. Any question under federal law would arise only from the railroad's anticipated defense based on the act of Congress, which is insufficient to confer jurisdiction under the settled interpretation of the jurisdictional statute.11
The Circuit Court lacked jurisdiction because the case did not arise under the Constitution or laws of the United States.12