In the United States, a standard employment contract is considered to be "at will," unless stated otherwise. That is, the employee serves at the pleasure of the employer, who reserves the right to terminate the work arrangement for any time, and without cause. However, termination of employment must be in accordance with federal and state anti-discrimination laws. Federally, employers are forbidden from relieving an employee of his/her duties due to their race, nationality, age, or religion. Various states have additional anti-discrimination categories of which the employer must be aware. Union employees are not "at will," and so employers must interact with them according to the relevant collective bargaining agreement (which stipulates payment, benefits, termination policies and other related measures), and applicable federal and state statutes.