This refers to the presumption that employment is for an indefinite period of time and may be terminated either by employer or employee. This is the historical approach that courts have taken in interpreting employment relationships. Given the unequal bargaining power between employees and employers, critics of this doctrine have noted its overly harsh results and have looked to unions, acting as certified representatives of employees, to equalize bargaining power. Such pro-union voices see unions as able to demand good faith bargaining on the part of the employer, job security, and other benefits.
By the end of the twentieth century, state courts found other exceptions to the doctrine of "at will" employment. The public policy exception bars an employer from terminating employees in violation of well-established public policy of the state. As an example, in many states an employee may not be terminated for filing a workers' compensation claim after an on-the-job injury. Many states do not allow employers to terminate employees for refusal to violate the law at the employer's request. Criteria for what violates public policy in a particular state varies from state to state.
The late twentieth century saw many states abandoning the "at-will" doctrine and an increase in protection of employee rights at work under a variety of theories including tort, contract, and property theories. A rise in such alternative means of redress has coincided with a steady drop in union membership in the private sector.