The Supreme Court ruled a former employee of Norfolk Southern Railway Co. can proceed with his lawsuit against the company in a state it’s not based.

In a 5-4 ruling Tuesday, the court upheld a Pennsylvania law that forces companies to face litigants within its borders when they register to do business there.

The question arose in a civil suit out of Pennsylvania, which is the only state with this kind of registration-jurisdiction regime. Opponents, however, feared a ruling upholding the law would open the door for other states to pass similar statutes.

Robert Mallory filed a lawsuit in Pennsylvania …