[This brief was filed in support of the petitioner in No. 16-405 (U.S., cert. granted Jan. 13, 2017).] BNSF Railway Co. should win this case, but on statutory grounds alone. BNSF makes three arguments: 1) That Daimler AG v. Bauman forbids Montana’s exercise of general personal jurisdiction here; 2) That Congress has not sought to license the state’s exercise of jurisdiction; and 3) That such a license would be void under the Fourteenth Amendment. BNSF’s first two arguments are fully persuasive and decide the case. As a result, the Court should decline to reach the third argument. Not only is it unnecessary to decide, it has the further defect of being wrong. Respondents’ case hinges on whether Congress in 1910 affirmatively licensed state personal jurisdiction over railroads doing business within state lines. It did not. The 1910 Act specified which federal courts might hear certain actions under the Federal Employers’ Liability Act. It did not say which state courts might do so—only *that* state courts might do so. Later discussions of doing-business jurisdiction in fact referred to a preexisting standard for state personal jurisdiction, established well before International Shoe. Respondents’ theory gets things backwards: Congress did not reshape state personal jurisdiction to fit the statutory rules for federal courts; rather, it shaped the statutory rules for federal courts to fit preexisting rules for state personal jurisdiction. While Congress in 1910 left state personal jurisdiction as it found it, this Court’s modern decisions have not. Respondents do not ask for Daimler to be overruled, nor do they deny that Daimler requires reversal in the absence of a statutory override. This is enough to end the case. That being so, the Court has no need to reach an important constitutional question. This Court has never squarely decided whether Congress may license the exercise of state personal jurisdiction that might otherwise be invalid. It should not do so in this case. “[N]ormally the Court will not decide a constitutional question if there is some other ground upon which to dispose of the case,” and here there are further reasons for reticence. The United States did not participate before the Montana courts, and limiting Congress’s power in this case may have the effect of striking down other federal statutes or may undermine ongoing legislative efforts and treaty negotiations. If the Court is going to restrict the power of Congress, it should wait for a case in which Congress has actually tried to use the power in question, and in which the United States has been available to defend it. The Court may be tempted to reach the issue regardless, simply because it seems easy—so easy, in fact, as to obviate any need for caution. Congress cannot license what the Constitution forbids, and the Constitution is widely thought to forbid particular types of personal jurisdiction. Yet that widespread belief is actually mistaken. When originally enacted, the Fifth and Fourteenth Amendments did not themselves impose any fixed limits on personal jurisdiction. They required only that a court *have* jurisdiction, over the subject matter as well as the parties—with the substantive doctrines of personal jurisdiction supplied by separate bodies of general and international law. The Fourteenth Amendment, in particular, was correctly understood by this Court in Pennoyer v. Neff to create a federal question of what had been merely a matter of general law, outside the scope of Article III appellate review. Modern doctrine is correct to hold that federal courts can review state judgments for their compliance with jurisdictional standards. But it is wrong to suggest that those standards are supplied by the Constitution itself, and so may not be altered by treaty or by Congress’s enumerated power under Article IV. To be clear: this brief does not suggest that the Court conduct its own inquiry as to the original law of due process, or even discuss the issue in any way. The necessary arguments were not briefed at the certiorari stage; they were not raised in the Montana courts; and they have been overlooked by decades of contrary decisions. Yet if the Court now finds itself in a deep hole of incorrect precedent, the least it can do is to stop digging. It should reverse and remand this judgment on statutory grounds, and it should wait for an appropriate case in which to consider the powers of Congress.