Talk of impeachment is everywhere. But when is it called for, and how does it work?

“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.”
— U.S. Constitution, Article II, section 4

If you find the rules of impeachment to be a bit hazy, you’re not alone. The impeachment of public officials in the U.S. is rare enough that we have only a few examples in history to inform our understanding. Since our nation’s founding, the House of Representatives has impeached two presidents, one senator, one cabinet officer, and fifteen judges. Of those, the Senate has convicted and removed eight judges from office. Both presidents and the senator remained.

Unsurprisingly, the highest profile impeachments have been of presidents. The House voted to impeach Presidents Andrew Johnson in 1868 and Bill Clinton in 1998, though both avoided conviction in the Senate. A third president, Richard Nixon, resigned from office to avoid impeachment following the Watergate scandal.

So, what kind of behavior does the Constitution consider impeachable, and how does the process work?

What Is an Impeachable Offense?
The Constitution enables the House of Representatives to impeach a high-ranking public official who it believes has committed “treason, bribery, or other high crimes and misdemeanors.” The definition of a high crime has been the subject of much debate over the years, but scholars generally understand it to include abuses of power.

Impeachment does not need to be linked to violation of a particular criminal statute. Alexander Hamilton wrote in Federalist Paper 65 that impeachment is a response to “offenses which proceed from the misconduct of public men, or, in other words, from the abuse or violation of some public trust.” This context is important. It tells us that impeachment is not intended to remove people from office simply because we don’t approve of their policies. Actions we disagree with may be good reasons to vote someone out of office in the next election, but they aren’t necessarily impeachable offenses.

By the same token, it is not legitimate to argue against impeachment by saying that it reverses the result of a valid election. The whole point of impeachment is to remove officials who are elected to office, but then abuse the power that comes with it.

What Is the Process?
In short, the process works like this: a House committee investigates alleged wrongdoing by a public official and may choose to bring articles of impeachment to the full House for a vote. In addition, any member of the House can introduce articles of impeachment on the floor without going through the committee process. In either case, if a majority of members of the House vote to impeach, then the official is impeached.

Next, the articles of impeachment move to the Senate, which holds a trial overseen by the chief justice of the U.S. Supreme Court. A team of legislators from the House, called “managers,” act as prosecutors while the Senate serves as the jury. The impeached official has defense lawyers. If two-thirds of senators vote to convict, then the official is removed from office. There is no appeal. This flowchart provides an easy-to-understand overview of the process.

Does the Public Have a Say?
As in all matters of public policy, Americans vote for elected officials to carry out their wishes, and we expect that these officials will vote in a way that reflects the views of their constituents. While this expectation is not always met, impeachment seems to be a place where public opinion does have weight.

An analysis by the Brookings Institution looked at how public opinion influenced past presidential impeachment efforts. President Nixon’s approval ratings fell from 50 percent to a dismal 24 percent as the Watergate hearings unfolded, and remained low. While support for impeaching Nixon was slow to gain steam in Congress, members of the House eventually began aligning themselves with public opinion. With the Judiciary Committee poised to approve three articles of impeachment against him, Nixon resigned.

Public support for President Clinton, on the other hand, remained high throughout his impeachment scandal. His approval ratings reached 73 percent at the end of 1998 when the House voted to impeach him, and stayed in the high 60s throughout the following year. With Americans largely supportive of the President, the Senate declined to convict.

Brookings also found that public support for the president isn’t the only factor in how Congress approaches impeachment. Americans’ sentiments toward the impeachment inquiry itself, and toward the House of Representatives, also appear to play a role.

What’s Next?
The Speaker of the House announced a formal impeachment inquiry last month. Six separate House committees have begun investigating the president. The White House and Congress are currently wrangling over whether an impeachment effort is valid because the full House has not voted to start one. Although nothing in the Constitution requires a full House vote at this juncture, impeachment proceedings against President Clinton did begin that way, and would have begun that way against President Nixon had he not resigned first.

The outcome of this current effort is impossible to predict. If history offers any guide, it will depend on the way Congress conducts the investigations and the trial, the evidence produced, and the impact of the evidence on public opinion over time.

Learn More

What’s a High Crime? Two scholars analyze Article II, Section 4 of the Constitution to better understand what actions warrant impeachment — via National Constitution Center

A Dubious Honor: In 1797, Tennessee Senator William Blount became the first American public official to be impeached. His offense? Conspiring with the British — via U.S. Senate: Art & History

Looking Back: A veteran political reporter writes about what he’s learned from covering two presidential impeachment efforts — via Los Angeles Times

Impeached: From a bribe-soliciting secretary of war to a tax-evading judge, these are the public officials impeached throughout American history — via House of Representatives: History, Art & Archives

Status Update: As of today, 227 members of the House support an impeachment inquiry. Keep track of where your member stands here — via Washington Post