Presidential executive orders are directives given federal employees by the president regarding a specified issue. The order remains published in the Federal Register for 30 days before taking effect, after which it is implemented without subjection to congressional mediation, either for or against.
Executive orders are usually designed to perform one of several functions. For example, it is common for such directives to address governmental management issues, particularly within the executive branch itself or other federal agencies. It is also possible for executive orders to aid the president in living up to constitutional requirements or duties. Despite the significant autonomy the president enjoys in issuing these directives, she must ensure that every component of the order is both legal and constitutional.
The president has the power to change or retract an order issued during her presidency, and there is no time constraint for doing so. Similarly, succeeding presidents can either keep pre-existing orders, revoke them or issue new orders superseding old ones. It is also possible for Congress to legislate a law dissolving the legality of an existing executive order, though such cases are extremely rare. Under these circumstances, however, the subject order can ultimately be vacated by the Supreme Court.