Executive powers

The president is head of the executive branch of the federal government and is constitutionally obligated to "take care that the laws be faithfully executed". The executive branch has over four million employees, including the military.

Administrative powers

Presidents make numerous executive branch appointments: an incoming president may make up to 6,000 before taking office and 8,000 more while serving. Ambassadors, members of the Cabinet, and other federal officers, are all appointed by a president with the "advice and consent" of a majority of the Senate. When the Senate is in recess for at least ten days, the president may make recess appointments. Recess appointments are temporary and expire at the end of the next session of the Senate.

The power of a president to fire executive officials has long been a contentious political issue. Generally, a president may remove executive officials purely at will. However, Congress can curtail and constrain a president's authority to fire commissioners of independent regulatory agencies and certain inferior executive officers by statute.

To manage the growing federal bureaucracy, presidents have gradually surrounded themselves with many layers of staff, who were eventually organized into the Executive Office of the President of the United States. Within the Executive Office, the president's innermost layer of aides (and their assistants) are located in the White House Office.

The president also possesses the power to manage operations of the federal government through issuing various types of directives, such as presidential proclamation and executive orders. When the president is lawfully exercising one of the constitutionally conferred presidential responsibilities, the scope of this power is broad. Even so, these directives are subject to judicial review by U.S. federal courts, which can find them to be unconstitutional. Moreover, Congress can overturn an executive order through legislation (e.g., Congressional Review Act).

Foreign affairs

Article II, Section 3, Clause 4 requires the president to "receive Ambassadors." This clause, known as the Reception Clause, has been interpreted to imply that the president possesses broad power over matters of foreign policy, and to provide support for the president's exclusive authority to grant recognition to a foreign government. The Constitution also empowers the president to appoint United States ambassadors, and to propose and chiefly negotiate agreements between the United States and other countries. Such agreements, upon receiving the advice and consent of the U.S. Senate (by a two-thirds majority vote), become binding with the force of federal law.

While foreign affairs has always been a significant element of presidential responsibilities, advances in technology since the Constitution's adoption have increased presidential power. Where formerly ambassadors were vested with significant power to independently negotiate on behalf of the United States, presidents now routinely meet directly with leaders of foreign countries.

Commander-in-chief

One of the most important of executive powers is the president's role as commander-in-chief of the United States Armed Forces. The power to declare war is constitutionally vested in Congress, but the president has ultimate responsibility for the direction and disposition of the military. The exact degree of authority that the Constitution grants to the president as commander-in-chief has been the subject of much debate throughout history, with Congress at various times granting the president wide authority and at others attempting to restrict that authority. The framers of the Constitution took care to limit the president's powers regarding the military; Alexander Hamilton explained this in Federalist No. 69:

The President is to be commander-in-chief of the army and navy of the United States. ... It would amount to nothing more than the supreme command and direction of the military and naval forces ... while that the power of the British king extends to the DECLARING of war and to the RAISING and REGULATING of fleets and armies, all of which ... would appertain to the legislature. Emphasis in the original.

In the modern era, pursuant to the War Powers Resolution, Congress must authorize any troop deployments longer than 60 days, although that process relies on triggering mechanisms that have never been employed, rendering it ineffectual. Additionally, Congress provides a check to presidential military power through its control over military spending and regulation. Presidents have historically initiated the process for going to war, but critics have charged that there have been several conflicts in which presidents did not get official declarations, including Theodore Roosevelt's military move into Panama in 1903, the Korean War, the Vietnam War, and the invasions of Grenada in 1983 and Panama in 1989.

The amount of military detail handled personally by the president in wartime has varied greatly. George Washington, the first U.S. president, firmly established military subordination under civilian authority. In 1794, Washington used his constitutional powers to assemble 12,000 militia to quell the Whiskey Rebellion—a conflict in western Pennsylvania involving armed farmers and distillers who refused to pay an excise tax on spirits. According to historian Joseph Ellis, this was the "first and only time a sitting American president led troops in the field", though James Madison briefly took control of artillery units in defense of Washington, D.C., during the War of 1812. Abraham Lincoln was deeply involved in overall strategy and in day-to-day operations during the American Civil War, 1861–1865; historians have given Lincoln high praise for his strategic sense and his ability to select and encourage commanders such as Ulysses S. Grant. The present-day operational command of the Armed Forces is delegated to the Department of Defense and is normally exercised through the secretary of defense. The chairman of the Joint Chiefs of Staff and the Combatant Commands assist with the operation as outlined in the presidentially approved Unified Command Plan (UCP).

Juridical powers and privileges

The president has the power to nominate federal judges, including members of the United States courts of appeals and the Supreme Court of the United States. However, these nominations require Senate confirmation before they may take office. Securing Senate approval can provide a major obstacle for presidents who wish to orient the federal judiciary toward a particular ideological stance. When nominating judges to U.S. district courts, presidents often respect the long-standing tradition of senatorial courtesy. Presidents may also grant pardons and reprieves. Gerald Ford pardoned Richard Nixon a month after taking office. Presidents often grant pardons shortly before leaving office, like when Bill Clinton pardoned Patty Hearst on his last day in office; this is often controversial.

Two doctrines concerning executive power have developed that enable the president to exercise executive power with a degree of autonomy. The first is executive privilege, which allows the president to withhold from disclosure any communications made directly to the president in the performance of executive duties. George Washington first claimed the privilege when Congress requested to see Chief Justice John Jay's notes from an unpopular treaty negotiation with Great Britain. While not enshrined in the Constitution or any other law, Washington's action created the precedent for the privilege. When Nixon tried to use executive privilege as a reason for not turning over subpoenaed evidence to Congress during the Watergate scandal, the Supreme Court ruled in United States v. Nixon, 418 U.S. 683 (1974), that executive privilege did not apply in cases where a president was attempting to avoid criminal prosecution. When Bill Clinton attempted to use executive privilege regarding the Lewinsky scandal, the Supreme Court ruled in Clinton v. Jones, 520 U.S. 681 (1997), that the privilege also could not be used in civil suits. These cases established the legal precedent that executive privilege is valid, although the exact extent of the privilege has yet to be clearly defined. Additionally, federal courts have allowed this privilege to radiate outward and protect other executive branch employees, but have weakened that protection for those executive branch communications that do not involve the president.

The state secrets privilege allows the president and the executive branch to withhold information or documents from discovery in legal proceedings if such release would harm national security. Precedent for the privilege arose early in the 19th century when Thomas Jefferson refused to release military documents in the treason trial of Aaron Burr and again in Totten v. United States 92 U.S. 105 (1876), when the Supreme Court dismissed a case brought by a former Union spy. However, the privilege was not formally recognized by the U.S. Supreme Court until United States v. Reynolds 345 U.S. 1 (1953), where it was held to be a common law evidentiary privilege. Before the September 11 attacks, use of the privilege had been rare, but increasing in frequency. Since 2001, the government has asserted the privilege in more cases and at earlier stages of the litigation, thus in some instances causing dismissal of the suits before reaching the merits of the claims, as in the Ninth Circuit's ruling in Mohamed v. Jeppesen Dataplan, Inc. Critics of the privilege claim its use has become a tool for the government to cover up illegal or embarrassing government actions.

The degree to which the president personally has absolute immunity from court cases is contested and has been the subject of several Supreme Court decisions. Nixon v. Fitzgerald (1982) dismissed a civil lawsuit against by-then former president Richard Nixon based on his official actions. Clinton v. Jones (1997) decided that a president has no immunity against civil suits for actions taken before becoming president, and ruled that a sexual harassment suit could proceed without delay, even against a sitting president. The 2019 Mueller Report on Russian interference in the 2016 presidential election detailed evidence of possible obstruction of justice, but investigators declined to refer Donald Trump for prosecution based on a United States Department of Justice policy against indicting an incumbent president. The report noted that impeachment by Congress was available as a remedy. As of October 2019, a case was pending in the federal courts regarding access to personal tax returns in a criminal case brought against Donald Trump by the New York County District Attorney alleging violations of New York state law.