The Constitution has a failsafe. When the framers decided to create a powerful chief executive with a fixed term of office, it was immediately evident that a remedy was needed in case something went terribly wrong. As Virginia delegate George Mason observed early in the deliberations in Philadelphia, “some mode of displacing an unfit magistrate is rendered indispensable by the fallibility of those who choose, as well as by the corruptibility of the man chosen.” The framers all agreed that the power to remove the executive would have to be lodged somewhere. They had more difficulty agreeing on who should control the removal power and on what basis it should be exercised.

There were essentially two options on the table. The president might be removable by either the state governments or by Congress. There was little interest among the nationalists who were working to rewrite the federal constitution in giving the states that kind of power over a branch of the national government, and so they quickly settled on giving the power to Congress. If Congress would have the authority to remove the president, it could either be done by impeachment or by what is sometimes known as “removal by address.” Impeachment was understood to require that a specific cause for removal be specified and a trial be held to determine whether the officer was guilty of those charges. Removal by address was a simpler process that merely required a vote with no necessity that specific charges be made or proven or that a fair hearing be provided. Because the framers valued the independence of the three branches of government and did not want the president to be at the mercy of a hostile legislature, they preferred the route of impeachment.

The constitutional text sets down both a procedure to be followed for impeachments and a substantive standard by which impeachments should be judged. Procedurally, an impeachment can be brought by a majority vote of the House of Representatives against any civil officer of the federal government. In practice, the House investigates whether impeachment charges would be warranted. If it determines that charges are warranted, articles of impeachment are drafted that specify the various charges against the officer in question and those are voted on by the whole House. Once the Senate receives articles of impeachment from the House, it organizes itself into a court. Senators take an oath to do “impartial justice according to the Constitution and the laws” when sitting as judges in that court, and the chief justice of the United States presides over the court in the case of an impeachment of the president. The House appoints managers to prosecute the case before the Senate, and the impeached officer is entitled to present a defense. At the conclusion of the trial, the members of the Senate must vote on each individual article of impeachment. Conviction requires a guilty verdict from two-thirds of the participating senators. Upon conviction, the Senate may impose a punishment of removal from office or disqualification from any future federal office.

Substantively, the Constitution specifies that impeachments can be brought for “treason, bribery, or other high crimes and misdemeanors.” The phrase “high crimes and misdemeanors” is borrowed from British parliamentary practice, but it does not have a settled or clear meaning. The constitutional drafters were searching for a standard that was flexible and would allow removal in a variety of situations as circumstances might dictate. But they also wanted a standard that required some specific, demonstrable offenses to have been committed before Congress would be able to remove members of the other branches of government.

While he was still a member of the U.S. House of Representatives, Gerald Ford famously quipped that “an impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history.” This is true in the sense that the Senate is the only court that can ever rule on the appropriateness of the House’s actions, and so if the Senate is willing to sustain an impeachment charge then it is for all practical purposes an impeachable offense.

Nonetheless, neither the constitutional framers nor the senators who have sat in impeachment trials have taken the view that Congress has complete discretion over the scope of impeachable offenses. In particular, the requirement that an officer must commit a specific high crime or misdemeanor to justify an impeachment has generally been understood to mean that mere policy disagreement, incompetence, innocent mistakes, or “maladministration” would not be an impeachable offense. Defendants in impeachment trials have an incentive to argue that the scope of impeachable offenses should be narrowly construed. If they are charged with private criminal behavior, they have argued that impeachable offenses must be limited to abuses of office. If they have been charged with abuses of office, they have argued that impeachable offenses must be limited to violations of the criminal law.

The House and Senate have generally taken a broader view of the impeachment power. If an officer has committed specific and serious bad acts that are fundamentally inconsistent with the requirements of their office or the expectations of the public trust, then the House and Senate have tended to be open to evaluating those as potentially impeachable offenses.

The history of federal impeachments has been fairly sparse. Across its entire history, the House has only passed articles of impeachment in 19 cases. In four of those cases, the individual left office before a verdict was rendered. The other cases are almost equally split between convictions and acquittals. In many cases where an impeachment might have been warranted, it was avoided. Cabinet members and lower-level executive officers either resign or are removed by the president when a sufficiently grave scandal erupts. Legislators resign, are expelled by their chamber, or are defeated in election. As a consequence, the history of federal impeachments is mostly a history of congressional investigations of federal judges and presidents. Most impeachments of federal judges have involved relatively pedestrian charges of unethical or criminal behavior. Congress has found itself pushed into action when judges with lifetime tenure face serious public scandals, and sometimes jail time, and yet refuse to voluntarily step down from the bench.

In many ways, the most discretionary impeachments have been those involving high-ranking officials, namely presidents and Supreme Court justices. Presidents and justices sometimes stumble into personal or political scandal, but those scandals are soon swept up into broader political debates. As a result, the fact and seriousness of their offenses are more disputed, and more legislators are willing to regard those offenses as tolerable. Even in hindsight, the handful of impeachment proceedings against justices and presidents has remained controversial. The one instance in which there was eventually some bipartisan agreement that impeachable offenses had been committed came out of Watergate, and in that case President Richard Nixon resigned rather than face likely impeachment and removal.

Undertaking a presidential impeachment is no small matter, and it should not be approached as if it were simply a technical application of the law. An impeachment will dominate the political agenda for months and throw the government into disarray. An unsuccessful effort to remove a president will leave the White House damaged and enfeebled. If supporters of the president are not persuaded that the impeachment effort was justified, it will escalate partisan tensions and feed distrust of American political institutions. Congress has a responsibility to pursue less drastic measures to address the perceived problems when it can. If an impeachment inquiry becomes unavoidable, political leaders on both sides of the aisle will have a duty to work together to find ways to overcome the resulting civil strife and put the nation on a stronger footing as it faces the challenges ahead.