Can you record your conversation with your coworkers without them knowing? Can you plant a listening device in your boss’s office? These are very different scenarios. Ruling in Lopez v. United States, Supreme Court Justice John Harlan sided with IRS agent Roger S. Davis, who recorded an innkeeper without their knowledge as Davis suspected they would offer him a bribe. Since the “device was used only to obtain the most reliable evidence possible of a conversation” in which the person using the hidden tape recorder “was a participant,” the one-party taping was legal. This holds for private citizens and government employees alike, though states or employers may have their own laws against the act. The use of listening devices, or the recording of conversations in which the taper is not present, is illegal. In some cases, the smoking gun may be best caught on tape. Read the rule to learn your rights surrounding taping.