In recent months, the U.S. Court of Appeals for the Fourth Circuit decided a number of Fourth Amendment cases that took umbrage with the “stop and investigate” techniques of law enforcement officers, in strongly worded critiques. During this same period, the court ruled that some stops and seizures were constitutional, thus drawing lines that may not be readily apparent to police officers. These cases are worth reviewing; they illustrate how challenging it may be to maintain law enforcement competence in the face of ever-shifting judicial oversight.