The Constitution gives Congress the authority to impeach and remove the President, Vice President, and other federal "civil officers" upon a determination that such officers have engaged in treason, bribery, or other high crimes and misdemeanors. Impeachment is one of the various checks and balances created by the Constitution, and is a crucial tool for potentially holding government officers accountable for violations of the law and abuse of power. Rooted in various constitutional provisions, impeachment is largely immune from judicial review. When considering impeachment matters, Members of Congress have historically examined the language of the Constitution; past precedents; the debates at the Constitutional Convention; the debates at the ratifying conventions; English common law and practice; state impeachment practices; analogous case law; and historical commentaries. Although the term "impeachment" is commonly used to refer to the removal of a government official from office, the impeachment process, as described in the Constitution, entails two distinct proceedings carried out by the separate houses of Congress. First, a simple majority of the House impeaches —or formally approves allegations of wrongdoing amounting to an impeachable offense, known as articles of impeachment. The articles of impeachment are then forwarded to the Senate where the second proceeding takes place: an impeachment trial. If the Senate, by vote of a two-thirds majority, convicts the official of the alleged offenses, the result is removal from office of those still in office, and, at the Senate's discretion, disqualification from holding future office. The House has impeached 19 individuals: 15 federal judges, one Senator, one Cabinet member, and two Presidents. The Senate has conducted 16 full impeachment trials. Of these, eight individuals—all federal judges—were convicted by the Senate. This report briefly surveys the constitutional provisions governing the impeachment power, examines which individuals are subject to impeachment, and explores the potential grounds for impeachment. In addition, it provides a short overview of impeachment procedures in the House and Senate and concludes with a discussion of the limited nature of judicial review for impeachment procedures. The House of Representatives shall chuse their Speaker and other Officers; and shall have the sole Power of Impeachment. —Article I, Section 2 The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors . —Article II, Section 4 The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two thirds of the Members present. Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States; but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law. —Article I, Section 3 The Constitution provides that impeachment applies only to the "President, Vice President, and all civil Officers of the United States," and that the grounds for impeachment are limited to "Treason, Bribery, or other high Crimes and Misdemeanors." The decision to impeach an individual rests solely with the House of Representatives. The House thus has discretion over whether to impeach an individual and what articles of impeachment will be presented to the Senate. The Senate, in turn, has the sole power to try impeachments. Conviction of an individual requires a two-thirds majority of the present Senators on one of the articles brought by the House. When conducting the trial, Senators must be "on oath or affirmation," and the right to a jury trial does not extend to impeachment proceedings. As President of the United States Senate, the Vice President usually presides at impeachment trials; however, if the President is impeached and tried in the Senate, the Chief Justice of the Supreme Court presides at the trial. The immediate effect of conviction upon an article of impeachment is removal from office, although the Senate may subsequently vote on whether the official shall be disqualified from again holding an office of public trust under the United States. If this option is pursued, a simple majority vote is required. Convicted individuals are still subject to criminal prosecutions for the same factual situations, and individuals who have already been convicted of crimes may be impeached for the same underlying behavior later. Finally, the Constitution bars the President from using the pardon power to shield individuals from impeachment or removal from office. In considering the use of the impeachment power, Congress confronts at least two preliminary legal questions bearing on whether an impeachment inquiry against a given official is constitutionally appropriate: first, whether the individual whose conduct is under scrutiny holds an office that is subject to impeachment and removal, and second, whether the conduct for which the official is accused constitutes an impeachable offense. The Constitution explicitly makes "[t]he President, Vice President and all civil Officers of the United States" subject to impeachment and removal. Which officials are to be considered "civil Officers of the United States" for purposes of impeachment is a significant constitutional question that remains mostly unresolved. In the past, Congress has seemingly shown a willingness to impeach Presidents, federal judges, and Cabinet-level executive branch officials, but a reluctance to impeach private individuals and Members of Congress. A question which precedent has not thus far addressed is whether Congress may impeach and remove subordinate, non-Cabinet level executive branch officials. The Constitution does not define "civil Officers of the United States." Nor do the debates at the Constitutional Convention provide significant evidence of which individuals (beyond the President and Vice President) the Founders intended to be impeachable. Impeachment precedents in both the House and Senate are equally unhelpful with respect to subordinate executive officials. In all of American history, only three members of the executive branch have been impeached: two Presidents and a Secretary of War. Thus, while it seems that executive officials of the highest levels are "civil Officers," historical precedent provides no examples of the impeachment power being used against lower-level executive officials. One must, therefore, look to other sources for aid in determining precisely how far down the federal bureaucracy the impeachment power might reach. The general purposes of impeachment may assist in interpreting the proper scope of "civil Officers of the United States." The congressional power of impeachment constitutes an important aspect of the various checks and balances that were built into the Constitution to preserve the separation of powers. It is a tool, entrusted to the House and Senate alone, to remove government officials in the other branches of government, who either abuse their power or engage in conduct that warrants their dismissal from an office of public trust. At least one commentator has suggested that the Framers recognized, particularly with respect to executive branch officials, that there would be instances in which it may not be in the President's interest to remove a "favorite" from office, even when that individual has violated the public trust. As such, the Framers "dwelt repeatedly on the need of power to oust corrupt or oppressive ministers whom the President might seek to shelter." If the impeachment power were meant to ensure that Congress has the ability to impeach and remove corrupt officials that the President was unwilling to dismiss, it would seem arguable that the power should extend to officers exercising a degree of authority, the abuse of which would be harmful to the separation of powers and good government. The writings of early constitutional commentators also arguably suggest a broad interpretation of "civil Officers of the United States." Joseph Story addressed the reach of the impeachment power in his influential Commentaries on the Constitution , asserting that " all officers of the United states [] who hold their appointments under the national government, whether their duties are executive or judicial, in the highest or in the lowest departments of the government , with the exception of officers in the army and navy, are properly civil officers within the meaning of the constitution, and liable to impeachment." Similarly, William Rawle reasoned that "civil Officers" included "[ a ] ll executive and judicial officers, fro m the President downwards , from the judges of the Supreme Court to those of the most inferior tribunals ..." Consistent with the text of the Constitution, these early interpretations suggest the impeachment power was arguably intended to extend to "all" executive officers, and not just Cabinet level officials and other executive officials at the highest levels. But who is an officer? The most thorough elucidation of the definition of "Officers of the United States" can be found in judicial interpretations of the Appointments Clause. That provision, which establishes the methods by which "Officers of the United States" may be appointed, has generally been viewed as a useful guidepost in establishing the definition of "civil Officers" for purposes of impeachment. The Appointments Clause provides that the President shall nominate, and by and with the Advice and Consent of the Senate, shall appoint Ambassadors, other public Ministers and Consuls, Judges of the supreme Court, and all other Officers of the United States, whose Appointments are not herein otherwise provided for, and which shall be established by Law: but the Congress may by Law vest the Appointment of such inferior Officers, as they think proper, in the President alone, in the Courts of Law, or in the Heads of Departments. In interpreting the Appointments Clause, the Court has made clear distinctions between "Officers of the United States," whose appointment is subject to the requirements of the Clause, and non-officers, also known as employees, whose appointment is not. The amount of authority that an individual exercises will generally determine his classification as either an officer or employee.