Abstract: Mallory v. Norfolk Southern Railway Co. presents the question whether the Fourteenth Amendment’s Due Process Clause prohibits Pennsylvania from requiring corporations to consent to general jurisdiction in order to do business there. The answer to that question is no. Neither the Court’s precedent nor the original Fourteenth Amendment forbids Pennsylvania from requiring such consent, nor from exercising jurisdiction once consent is secured. What may invalidate Pennsylvania’s requirement, however, is the Court’s modern doctrine on the “dormant” component of the Commerce Clause, which is currently thought to restrict state laws imposing serious burdens on out-of-state economic actors. The difference between due process and dormant commerce matters: substantive requirements of the Fourteenth Amendment may not be relieved by Congress or by treaty, while dormant commerce restrictions might be. The Court should not limit state jurisdiction under a mistaken due process theory that in passing also limits the authority of Congress (and of the President and Senate). Instead, the regulation of interstate corporate activity should be left up to the Interstate Commerce Clause, to be addressed by the state courts on remand.