Workplace defamation actions face a number of obstacles. The one that probably comes up the most is the issue of qualified privilege. Employees often claim that a manager or supervisor defamed them in the course of a termination or negative performance evaluation. These statements are usually protected from defamation claims, as a limited privilege applies to communications made on any subject matter in which the person communicating has an interest, or with reference to which he has a duty, if made to another person having a corresponding interest or duty. In other words, in situations where it is necessary or expected that one employee will make statements concerning the performance of another (such as a performance evaluation), a qualified privilege will apply.
Another defense that is sometimes raised in the employment context is that of “intra-corporate immunity.” This is a defense borrowed from the law of conspiracy. Because a conspiracy, by definition, requires at least two legally distinct persons, and because two employees acting within the scope of their employment duties are both acting as agents of their employer, a conspiracy cannot be formed between those two employees due to the unity of interest and absence of a second entity. “A corporation cannot conspire with itself,” is the oft-used way of describing the reasoning behind the doctrine.