An executive order is a legally binding edict issued by a member of the executive branch of a government, usually the head of that branch.
In the United States, Presidents have issued executive orders since 1789. There is no Constitutional law or statute that explicitly permits this, aside from the vague grant of "executive power" given in Article II, Section 1 of the Constitution and the statement "take Care that the Laws be faithfully executed" in Article II, Section 3. However, executive orders have legal force unless in conflict with a law approved by the Legislative or a court decision by the Judicial branch of government.
Most executive orders are directed to various Federal Administrative Agencies or departments of the Executive Branch to help orchestrate those agencies in their duties. Other executive orders, called Proclamations, serve a more ceremonial purpose, such as declaring new holidays and celebrations. Others, known as National Security Directives or Presidential Decision Directives, deal with national security and defense.
Until the early 1900s, executive orders went mostly unannounced and undocumented, seen only by the agencies to which they were directed. Others have simply been lost due to natural decay and poor record keeping. However, the State Department instituted a numbering system for executive orders in the early 1900s, starting retroactively with President Abraham Lincoln's Emancipation Proclamation in 1862. Today, only those executive orders dealing with issues of national security are kept from the public.
Until the 1950s, there were no rules or guidelines outlining what the President could or could not do through an executive order. However, the Supreme Court ruled that an executive order from President Harry S. Truman that placed all steel mills in the country under federal control was invalid because it attempted to make law, rather than clarify or act to further a law put forth by the Congress or the Constitution. Presidents since this decision have generally been careful to cite which specific laws they are allegedly furthering when making new executive orders.
Many critics have accused the Presidents of abusing executive orders, both to make new laws without Congressional approval and to move existing laws away from their original mandates. Large policy changes with wide-ranging effects have been passed into law through executive order, including the integration of the Armed Forces under Harry Truman and the desegregation of public schools under Dwight D. Eisenhower. Even entire wars have been fought upon executive order, including Bill Clinton's 1999 Kosovo War. Critics fear that the President could make himself a de facto dictator by side-stepping the other branches of government and making autocratic laws. The Presidents, however, cite executive order as often the only way to clarify laws passed through the Congress, laws which often require vague wording in order to please all political parties involved in their creation.
To date, the courts have only overturned two executive orders: the aforementioned Truman order, and a 1996 order issued by President Bill Clinton which attempted to prevent the U.S. government from contracting with organizations that had "strikebreakers" on the payroll. Likewise, the Congress may also overturn an executive order by passing legislation in conflict with it or refusing to approve funding to enforce it. Because the President retains the power to veto such a decision, however, the Congress usually needs a 2/3 majority to override a veto and truly end an executive order.