Mr. Justice Holmes

delivered the opinion of the court.

This is an action for breach of a contract to furnish plaintiff, (defendant in error,) a special train to carry him from Reno, Nevada, to Doyle, California, where his son was ill, and to bring the two back from that place. The plaintiff got a judgment, and the only question before us is whether any rights of the defendant under the Act to Regulate Commerce have been infringed. The ground on which such an infraction is alleged is that the trial court, after the trial had been going on for more than a day, refused to allow the answer to be amended so as to set up that no tariff rate for special trains had been filed by the defendant and that therefore the contract was illegal. The defendant had mentioned the point at the beginning of the trial but this was the first time that it was presented *105 in proper form, under the state practice, although some months had elapsed since the beginning of the suit and demurrers and other defences had been interposed without suggesting this one. The Supreme Court of the State declined to overrule the discretionary judgment of the court below. 38 Nevada, 156.

Upon the question whether a claim of immunity under a statute of the United States has been, asserted in the proper manner under the state system of pleading and practice “the decision of the state court is binding upon this court, when it is clear, as it is in this case, that such decision is not rendered in a spirit of evasion for the purpose of defeating the claim of federal right.” Atlantic Coast Line R. R. Co. v. Mims, 242 U. S. 532, 535. The most that could be said in this case was that the Supreme Court was influenced in its judgment by the fact that the railroad, after treating the plaintiff very badly, was trying to escape liability by an afterthought upon a debatable point of law — not at all by the fact that the law involved was federal. The plaintiff had tried the case relying upon the presumption which was sufficient as the pleadings stood. Cincinnati, New Orleans & Texas Pacific Ry. Co. v. Rankin, 241 U. S. 319. The court reasonably might decline to put him to procuring other evidence from a distance, on the last day of the trial, upon a new issue presented after his evidence was in. We perceive no reason why this court should interfere with the practice of the State.

Writ of error dismissed.

The Chief Justice and Me. Justice Claeke dissent.