430 HARVARD LAW REVIEW tax illegal; yet the plaintiff was unable to recover. Lord Coleridge said: "Here at the time the money was paid, which was before Dobbs's case, the law was in favor of the company, and there was no authority to show that it could be recovered back on account of a judicial de- cision reversing the former understanding of the law." The case has been followed in the United States," though there are opinions to the contrary. ^2 The true theory of such cases is not that decisions of the courts are evidence of the law, that the earlier decision is merely a poor exposition of the rule, that the law was always in accordance with the later judgment, and that money paid under mistake of law is lost to the payer; but that decisions of the courts make the law,^^ that the payment was in truth a legal payment at the time it was made, and, there being no mistake, it cannot be recovered. The view of the analytical jurists, that the judges make the law, has as much ap- plication where a court has vacillated in considering the constitution- ality of a statute, as where it has changed its mind on a principle of the common law.^'* Nor can the carrier claim that it rendered the serv- ices under duress and that value so given without consideration may be recovered. For, if the duress is according to law at the time exercised, the defendant can stand on his legal rights then acquired, although the highest court later sees fit to change the rule for the future. It is true that the decree of the Supreme Court of the United States under which the North Dakota carriers rendered the statutory services was peculiar in that it contained the provision "without prejudice." The court's own opinion of the nature of this decree, however, seems to be that it is final as to transactions between it and any subsequent decree prescribing a different rule. Whether the object of the reser- vation is — as ordinarily — to give the carrier or the state, as the case may be, an opportunity to demonstrate by actual practice a question diflficult of proof without experiment,^^ or to leave a loophole for change of circumstances,^® the Supreme Court has felt this qualification "not to leave open the controversy as to the period with which the decree dealt and which it concluded." ^^ " Metzger v. Greiner, 9 Ohio C. Ct. R. (n. s.) 364; Kenyon v. Welty, 20 Cal. 637. And see Hardigree v. Mitchum, 51 Ala. 151; Pittsburgh Co. v. Lake Co., 118 Mich. 109, 76 N. W. 395 ; Lejon v. Richmond, 2 Johns. Ch. (N. Y.) 51; Harris v. Jex, 55 N. Y. 421 (1874). " Centre School Township v. State, 150 Ind. 168, 49 N. E. 961. " Gray, Nature and Sources of the Law, §§ 465-512, 535-50; 2 Austin, Jur., 4 ed., 655; Gelpcke v. Dubuque, i Wall. (U. S.) 175; Kuhn v. Fairmont Coal Co., 215 U. S. 349. For the view that judicial decisions are merely evidence of preexist- ing law see i Blackstone, Commentaries, 68-71,4 Ill.L. Rev. 533; Swift 0, Tyson, 16 Pet. (U. S. ) I. " Gelpcke v. Dubuque, i Wall. (U. S.) 175. " Knoxville v. Water Co., 212 U. S. i, 19; Willcox v. Consolidated Gas Co., 212 U. S. 19, 54, 55; Northern Pacific Ry. v. North Dakota, 216 U. S. 579, 581; Louis- ville V. Cumberland Tel. & Tel. Co., 225 U. S. 430, 436; Des Moines Gas Co. v. Des Moines, 238 U. S. 153, 173. 1' Minnesota Rate Cases, 230 U. S. 352, 473. " Missouri v. C. B. & Q. R. R., 241 U. S. 533, 541. Here statutory rates had been enjoined by the United States Circuit Court. On appeal to the Supreme Court the injunction was dissolved without prejudice. The state then brought original action in the Supreme Court for excess fares paid by the officers. The carrier again at- J
