A contentious issue in recent years has been the President's power to issue executive orders, which take the form of law but aren’t generated by Congress. The Constitution nowhere says explicitly, “The President can issue executive orders.” But as with the “necessary and proper” clause, that hasn’t stopped Congress or the President from doing things that are nominally within their purview. So an executive order is a pronouncement by the President that has the force of law but isn’t something that came to the President’s desk from Congress. An executive order remains in force until it is canceled or revoked; some executive orders have an end date and so expire that way. A President has the power to change or rescind executive orders made by previous Presidents.

The nation's first President, George Washington, issued a handful of executive orders, including one declaring a federal holiday of Thanksgiving. Not surprisingly, every President (with the exception of William Henry Harrison, who didn’t serve more than a couple of months in office) has issued at least one executive order. Until very recent times, these have taken a rather bland form because they are basically instructions to the people who report to the President, meaning the members of the Executive Branch.

The exceptions to the blandness began during World War I. The first War Powers Act, in 1917, gave President Woodrow Wilson broad powers to prosecute war, and he did so, in some cases by issuing executive orders. Another famous example of an executive order was the Emancipation Proclamation, which Abraham Lincoln issued during the Civil War. That one declared free all slaves then in rebel-held territory, and so as Union troops seized control of that territory, those occupations made the slaves there free.

The executive order is not an exercise of absolute power. It can be nullified, by a law passed by Congress. A Supreme Court decision can nullify an executive order as well.

One infamous example of an executive order was Number 9066, which President Franklin D. Roosevelt issued in 1941. That one ordered the internment of more than 120,000 Japanese-Americans, many of whom were U.S. citizens. Another Roosevelt executive order that has been considered both famous and infamous was Number 8807, which created the agency that spawned the Manhattan Project, which developed the atomic bomb.

As could probably be predicted, the President who issued the most executive orders was Franklin Roosevelt, with 3,721. (The first of those declared a "bank holiday," to help deal with a money crisis during the Great Depression.) Most of the rest dealt with combating the economic downturn and fighting World War II. Roosevelt’s successor, Harry Truman, was a big fan, issuing 907 executive orders in just five years in office. One of those ended racial segregation in the U.S. Army. Another gave the federal government control of the country's steel mills (although the Supreme Court held, in Youngstown Sheet & Tube Co. v. Sawyer (1952) that that executive order was unconstitutional. In a similar vein, The Court, in 1935 alone, overturned five of President Franklin Roosevelt's executive orders.

Other Presidents issuing more than one thousand executive orders were Woodrow Wilson (1,803), Calvin Coolidge (1,203), and Theodore Roosevelt (1,081).

Other famous executive orders:

• President Dwight D. Eisenhower, in 1957, used an executive order to place the National Guard in charge of keeping the peace as the "Little Rock Nine" attended an Arkansas high school.
• President John F. Kennedy, in 1961, issued one that created the Peace Corps.
• After the assassination of Kennedy, in 1963, President Lyndon B. Johnson created the Warren Commission to investigate Kennedy's death.
• President Gerald Ford, in 1974, issued one that pardoned Richard Nixon, who had recently resigned the presidency.
• In the wake of the shock after the 9/11 attacks, President George W. Bush, in 2001, issued one that created the Department of Homeland Security.