The Stewardship Theory of the President states that the President is the steward of the people, who must act in their best interests at all times. The theory was promoted by Theodore Roosevelt.

Although Congress has come close to removing four Presidents from office, none has ever been removed from office due to impeachment. Congress introduced a resolution to impeach John Tyler over the issue of states’ rights, but the resolution failed; Andrew Johnson was impeached for his handling of the Reconstruction Era, but he was found not guilty in his senate trial (by one vote); Richard Nixon, who might have become the first President to be removed from office due to impeachment, resigned during the process; Bill Clinton's case went to the Senate, where he was found not guilty. Because a two-thirds vote is needed to convict the President in the Senate, it is very difficult to convict a President during an impeachment (his party will likely support him unless doing so will cause such a massive drop in public support).

The President is given numerous powers under the Constitution—including Executive Clemency, which allows the President to pardon criminal offenders. The President has many powers related to war and foreign relations. The President may appoint ambassadors, receive foreign ambassadors, and negotiate treaties with foreign nations. The President, however, cannot ratify a treaty. For a treaty that is negotiated by the President to be ratified, it must be approved by a two-thirds vote in the Senate.

Ever since Franklin Roosevelt greatly expanded the powers of the Presidency, during the New Deal era of American history, the nation’s policy agenda has more and more often been set by the President. The expanding power of the Presidency is one of the defining traits of twentieth-century American politics.

The Environmental Protection Agency (EPA) was first proposed and established by President Richard Nixon in 1970. Its purpose is to regulate the conduct of businesses and individuals for the purpose of protecting the environment and human health.

A lame-duck president is one who has been voted out of office or finds his or her term limit has expired, but is still serving as president for a few months until the inauguration of the new president. The term is generally used solely to refer to a president who has been voted out of office; it is generally thought that he or she has lost the mandate of the people and therefore cannot try to pass any significant legislation for the remainder of his or her term—he or she is a "lame duck." Probably the most notable lame duck president of the twentieth century is Herbert Hoover, who was voted out of office during the early years of the Great Depression in favor of Franklin D. Roosevelt.

There are three main types of powers held by the President: enumerated powers, powers granted by Congress, and inherent powers. Enumerated powers are those given to the President in the Constitution. Powers granted by Congress are just as the name states. And, inherent powers are those that the President has that are derived from either of the two categories, and exist to allow the President to complete his duties. Of the powers listed above, all besides “to issue a veto” are inherent powers. The President has the power “to issue a veto” according to Article 1, Section 7 of the Constitution, making it an enumerated power.

The President is the only person (thus the Executive the only branch) who can recognize new governments. This is somewhat of a read-between-the-lines tradition that stretches back all the way to Washington, who interpreted the clause “[the President may] receive Ambassadors” to mean that the President had the sole ability to recognize new governments. President Truman, for example, recognized the state of Israel.

A treaty is the only device which is explicitly mentioned by the Constitution. One of the recurring themes of American Politics, however, is institutions looking beyond the “four corners” of the Constitution for power. The president does so in terms of war by his (constitutional) ability to direct troop movements which he can (extra-constitutionally) use to intervene in foreign affairs without the Congressional consent necessary to declare war. The president does something similar with executive agreements. The President has the (constitutional) ability to create treaties—the downside to treaties, however, is that they must be ratified by the Senate. Presidents have maneuvered around that requirement, however, by using an (extra-constitutional) device called the “executive agreement.” An executive agreement is basically exactly what it sounds like—two heads of state agreeing to something. Clearly, however, it must come with more strings attached than just a treaty (because it, unlike a treaty, is not ratified by Congress). An executive agreement cannot supersede existing law, on top of which Congress may pass a law nullifying it, and the courts may strike it down as unconstitutional. 

Upon inauguration, the President and Vice President must be natural born citizens, at least 35 years of age, and United States residents for at least 14 years.