During his first week in office, President Trump has signed a number of executive orders, affecting a range of policies from trade to health care to immigration. Here is what you should know about executive orders:

What is an executive order?

An executive order is an official document, signed by the president, used to manage the Federal Government.

Are executive orders legally binding?

Yes, assuming they are limited to the scope of the executive action allowed by a president, an executive order has the power of federal law. While a president cannot directly create a new law or sign an executive order that violates existing law, he or she can use an executive order to specify how laws will be carried out or direct how a federal agency will carry out a task.

By what authority can a president issue an executive order?

As the Congressional Research Service notes, “The U.S. Constitution does not define these presidential instruments and does not explicitly vest the President with the authority to issue them. Nonetheless, such orders are accepted as an inherent aspect of presidential power.” Their authority is assumed to be derived from implementing the “Take Care Clause” (The President] shall take Care that the Laws be faithfully executed….) of Article II, Section 3.

How many executive orders have been issued?

As of today, there are 13,765 executive orders. Since the Hoover administration they have been numbered consecutively, so you can tell how many have been published by looking at the number of the latest issued by the most recent president.

Where are executive orders found?

After they are signed by the president, the text of the executive order is entered into the Federal Register. (You can find the text of all executive orders since the administration of President Clinton online here).

Have presidents always used executive orders?

Yes. George Washington was the first president to sign issue an executive order. The only president who did not issue an executive order was William Henry Harrison, who died 31 days after taking office.

Which president issued the most/fewest executive orders?

Franklin D. Roosevelt issued the most (3,522), followed by Woodrow Wilson (1,803) and Calvin Coolidge (1,203). John Adams, James Madison, and James Monroe all tie for the fewest (excluding Harrison) with one each.

Can an executive order be overturned?

Yes. The president is free to revoke, modify, or supersede his own orders or those issued by a predecessor. The Supreme Court in Youngstown Sheet & Tube Co. v. Sawyer also established the framework for determining whether an executive order is Constitutional.

What are the most notable executive orders?

While it’s difficult to choose the most noteworthy out of 13,000 executive orders, here are six worthy of notice:

Unnumbered (Lincoln): Authorized the suspension of Writ of Habeas Corpus.

Executive Order 8807 (FDR): Established the Office of Scientific Research and Development,which created the atomic bomb.

Executive Order 9981 (Truman): Abolished racial discrimination in the U.S. military and eventually led to the end of segregation in the services.

Executive Order 9066 (FDR): Authorized the Secretary of War to prescribe certain areas as military zones, clearing the way for the deportation of Japanese Americans, German Americans and Italian-Americans to internment camps.

Executive Order 10730 (Eisenhower): Sent Federal troops to maintain order and peace during the integration of Central High School in Little Rock, Arkansas.

Executive Order 5658 (Hoover): An executive order on the form, style, and safeguarding of executive orders and proclamations.

(Note: I excluded the Emancipation Proclamation since they are similar, but not quite the same, as executive orders.)