Wrongful termination of an employee occurs when an employer fires an employee for illegal reasons. Such a termination is typically done through an express action by the employer. However, there are certain situations in which the employer may attempt to make the employee quit on their own terms.
Such an action is known as constructive dismissal, or constructive discharge. Essentially, the employer creates a work environment for the employee that is so unacceptable that they are compelled to quit their employment. Such a dismissal is considered wrongful when the employee is targeted for an illegal reason, in violation of an employment contract or in a way that is contrary to public policy. If the employer's actions rise to such a level, the employee's resignation is disregarded as the employer is viewed as having fired the employee in an involuntary manner.
Under California law, in order to establish that a constructive discharge occurred the employee must prove certain elements. These elements include the presence of a working environment that was so negative and abnormal that any reasonable employee would have quit under the same circumstances. Additionally, the employee must prove that their employer was either aware of the adverse working conditions or intended to make them quit. The working conditions in question must be extreme and constitute a pattern of behavior, unless there are severe incidents to which the employee is exposed.
As the majority of employees are considered at-will, courts do not typically require that their work environment be completely stress free or that they be treated fairly at all times. However, if they are targeted or discriminated against by their employer for such actions, they may have a legal claim against their employer for wrongful termination.
Source: Findlaw, "Constructive Dismissal and Wrongful Termination," accessed on Aug. 9, 2015