Mallory v. Norfolk Southern Railway Co. involves a Pennsylvania law that requires corporations to register in the state if they want to do business there. The question in the case is whether that registration is enough for personal jurisdiction when the corporation is sued. Robert Mallory worked for the railroad company, and when he got an illness from his job, sued in Pennsylvania. Because of the registration law, once the company registered to do business in the state, they became subject to lawsuits there. Mallory is from Virginia and the railroad company is based in Virginia. Mallory argues that the Pennsylvania law is constitutional even when applied in situations like his. Norfolk Southern Railway Co. argues that the law violates the Due Process Clause of the 14th Amendment. 

If Mallory wins, the ruling will allow corporations who register to do business in a state to be sued there. 

If Norfolk Southern Railway Co. wins, Pennsylvania’s and other states’ similar laws will be unconstitutional and plaintiffs will need a stronger jurisdictional argument to challenge big corporations.