Two weeks ago, CNN reported that “White House lawyers have begun researching impeachment procedures in an effort to prepare for what officials still believe is a distant possibility that President Donald Trump could have to fend off attempts to remove him from office.” More broadly, the conversation has shifted from implying the possibility of impeachment to overtly discussing it: Senator Angus King (I-ME) for example stated on live television that we seem to be “moving toward an impeachment process.” The orchestral calls for impeachment are waxing. Even here on Lawfare the tenor has changed: articles written just a few weeks ago noted the role of impeachment as a formal check on presidential power—in the abstract—or as “a long-shot”; more recent articles discuss the partisan optics of impeachment or outright assume we are in “impeachment territory.”

So this is probably a good time for a primer on the mechanics of impeachment. How exactly, is a president impeached, and what happens when he is? In short, there’s no one answer, just a framework. Because the Constitution permits impeachment without prescribing the nuances of its execution, past practices have not necessarily been consistent and, by extension, may not dictate future proceedings should we reach that point.

This post aims to explicate in some detail the framework and both past proposed and executed impeachment procedures.

The Constitution

In the Constitutional Convention, the issue of impeachment was discussed at length, primarily as to whether and on what grounds an officer should be impeachable. Delegates, however, paid short shrift to how an impeachment proceeding at the highest level is to occur.

Having concluded it best for the nation to have a check on Executive Power, the drafters came up with Article II § 4 of the Constitution, which states: “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.” A chorus already exists—on Lawfare and elsewhere—asking what constitutes an impeachable offense, so I won’t contribute to the cacophony except to add the pragmatism of then-Minority Leader Gerald Ford: “The only honest answer is that an impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history.” Notably, even the Framers debated how the Impeachment Clause ought to read and were not unanimous as to their meaning.

The Constitution only discusses impeachment procedure in 3 clauses in Article I—§ 2 Clause 5 and § 3 Clauses 6 and 7:

§ 2, Clause 5: The House of Representatives . . . have the sole Power of Impeachment. … § 3, Clause 6: 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. … § 3, Clause 7: 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.

Consider the impeachment process as having a rough analogue in a pedestrian criminal case: the House choosing to impeach the officer on an article of impeachment is kind of like a grand jury’s choice to indict a person for a crime; the Senate sits as the empaneled jury and tries the case. But the Constitution requires nothing beyond the House’s vote to impeach, the Senate’s trying and convicting the impeached by a two-thirds vote, and the Chief Justice’s presiding over the trial if the President is tried (the Presiding Officer of the Senate is typically the Vice President).

So how do we put meat on these very bare bones? Without a constitutionally or statutorily prescribed procedure, our best bet is to analyze modern impeachment proceedings—both Presidential and otherwise—and current Senate Rules to see what lessons we can draw.

Drawing and Referring Articles of Impeachment

Three Presidents have had articles of impeachment drawn up and reported to the full House of Representatives: Andrew Johnson, Richard Nixon, and Bill Clinton. Famously, only two have passed the lower chamber: the articles drawn up against Nixon never came to pass, as he resigned shortly before the full House had the opportunity to vote. Though all three cases were different (in procedure and in substance), some common threads exist.

First, articles are themselves resolutions a la run-of-the-mill legislation. There are four kinds of legislation: bills, joint resolutions, concurrent resolutions, and simple resolutions. Bills and joint resolutions have no practical difference—both have the force of law and require a Presidential signature—save that only the latter can be used to amend the Constitution (in which case the President’s signature is not required). Bills and joint resolutions are thus where the vast majority of laws emanate from, such as social programs or economic measures. For obvious reasons, articles of impeachment would therefore not be bills or joint resolutions.

And as the House of Representatives’ website explains, “[m]atters affecting the operations of both the House of Representatives and Senate are usually initiated by means of concurrent resolutions,” while “[a] matter concerning the operation of either the House of Representatives or Senate alone is initiated by a simple resolution.” The Library of Congress also notes that concurrent or simple resolutions “express the collective opinion . . . on public policy issues” of both or one chamber, respectively. Because the power to impeach rests with the House alone, articles of impeachment take the form of simple resolutions.

Second, there may be precursor legislation to the articles of impeachment themselves. On December 4, 1865, Representative Thaddeus Stevens of Pennsylvania, the ardent abolitionist leading the charge for the 13th Amendment, “introduce[d] a resolution to create a Joint Committee on Reconstruction.” The Joint Committee then introduced its own Resolution urging Johnson’s impeachment, “which passed the House on February 24, 1868, by a vote of 126 to 47.” Only thereafter did the House establish an impeachment committee, which drafted Johnson’s eleven articles of impeachment.

The Nixon and Clinton impeachments involved different precursor legislations, but they buttress the underlying principle; instead of creating a new committee, both Congresses charged the Judiciary Committee to review impeachment. In 1974, House Resolution 803 “[a]uthorize[d] the House Committee on the Judiciary to investigate fully and completely whether sufficient grounds exist for the House of Representatives to impeach President Richard M. Nixon.” Only after the House Judiciary Committee performed its own investigation did the Committee write up articles of impeachment.

On the other hand, the House Judiciary Committee relied on the Starr Report for the substantive investigation of President Clinton’s wrongdoing. Then the House passed House Resolution 581 in 1998, charging:

the Committee on the Judiciary, acting as a whole or by any subcommittee thereof appointed by the chairman . . . to investigate fully and completely whether sufficient grounds exist for the House of Representatives to exercise its constitutional power to impeach [President Clinton and] report to the House of Representatives such resolutions, articles of impeachment, or other recommendations as it deems proper.

Thereafter, the House passed House Resolution 611, entitled Impeaching William Jefferson Clinton, President of the United States, for high crimes and misdemeanors.

As of today, the House and Senate Intelligence Committees have been holding their own investigations into Russian meddling in the elections; a special prosecutor has been appointed, too. The exact scope of each investigation is beyond this article, except to say that these investigations could take the place of any analogous actions or conclusions regarding impeachable offenses the Judiciary Committees could undertake (a la Clinton), or they could compel the Judiciary Committee to perform yet another substantive examination of the matter with a particular eye on impeachment (a la Nixon).

Third, the articles can come from anywhere. The House does have particular rules for the introduction of legislation: for example, any Member can introduce any piece of legislation at any time, and it “is assigned its legislative number by the Clerk and referred to the appropriate committee by the Speaker, with the assistance of the Parliamentarian.” The committees—and subcommittees—then do much of the heavy lifting, debating the merits and demerits of proposed laws in hearings and commissioning reports on the law’s hypothetical effects. This would be the case here as well. What’s more, in the words of the Congressional website, “[a] committee may table a bill or fail to take action on it, thereby preventing its report to the House [to be voted on by all 435 Members]. This makes adverse reports or reports without recommendation to the House by a committee unusual.” I leave it to others as to whether a Judiciary Committee would vote such a measure out of committee and whether Speaker of the House Ryan would put it to a floor vote. It is reasonable to expect as a threshold matter, however, that any articles of impeachment would be referred in the first instance to the Judiciary Committee or would emerge from that committee.

But because articles of impeachment are just like any other resolution, they are also subject to a discharge petition—a mechanism that can force a vote over the will of the Speaker and majority party leadership. The rules for these petitions are quite in the weeds, but the upshot is that if a majority of Members sign a discharge petition, it can be forced onto the floor for a vote. Though discharge petitions are a rare artifact these days, they are not unheard of: House Democrats attempted to use one to “create an independent, bipartisan, outside commission to investigate foreign interference in the 2016 election” before the appointment of Mr. Mueller and are circulating another one that would require President Trump to release his taxes. Thus, though prior articles have emanated from the House Judiciary Committee, that need not be the case: sufficient support is sufficient support.

The Senate Trial

As Alexander Hamilton wrote in The Federalist No. 65, “Where else than in the Senate could have been found a tribunal sufficiently dignified, or sufficiently independent?” Unfortunately, Hamilton and his brethren forewent giving particularized procedures for impeachment. Thus, the typical interests—i.e. equity, fairness, reasonableness, etc.—that place strict constitutional limits on legal trials are not required of impeachment trials. Consequently, the rules—made by Senate resolution—are governed by the whims of the 100 men and women with offices in the Dirksen, Hart or Russell buildings.

This certainly impacts the trial itself. As Charlie Savage wrote in the New York Times:

“When the Senate decided what the rules were going to be for our trial, they really made them up as they went along,” said Greg Craig, who helped defend Mr. Clinton in his impeachment proceeding . . . . The rules adopted by the Senate in the Clinton trial . . . made it harder to prove a case compared with trials in federal court, said former Representative Bob Barr, a Georgia Republican who served as a House manager during the trial and is also a former United States attorney. “Impeachment is a creature unto itself,” Mr. Barr said. “The jury in a criminal case doesn’t set the rules for a case and can’t decide what evidence they want to see and what they won’t.”

Therefore, any prediction of what an impeachment trial would look like rests at a minimum on the assumption that any rules adopted will not be changed. But assuming this, we have some idea of what a trial would look like from the standing set of Rules for Impeachment in the Senate Manual. The Rules take up only 9 pages and are comprised of 26 individual rules (substantially similar if not identical to those of Congresses past).

Before going into the details of how the day-to-day operations work, it is important to look at the foundational structure of the trial. Here, some familiar elements appear. For example, under Rule IV, like a court, the Senate has:

[the] power to compel the attendance of witnesses, to enforce obedience to its orders, mandates, writs, precepts, and judgments, to preserve order, and to punish in a summary way contempts of, and disobedience to, its authority, orders, mandates, writs, precepts, or judgments, and to make all lawful orders, rules, and regulations which it may deem essential or conducive to the ends of justice. And the Sergeant at Arms, under the direction of the Senate, may employ such aid and assistance as may be necessary to enforce, execute, and carry into effect the lawful orders, mandates, writs, and precepts of the Senate.

The trial also has some scope limitations under Rule VII:

[T]he Presiding Officer on the trial shall direct all the forms of proceedings while the Senate is sitting for the purpose of trying an impeachment, and all forms during the trial not otherwise specially provided for. And the Presiding Officer on the trial may rule on all questions of evidence including, but not limited to, questions of relevancy, materiality, and redundancy of evidence and incidental questions, which ruling shall stand as the judgment of the Senate, unless some Member of the Senate shall ask that a formal vote be taken thereon, in which case it shall be submitted to the Senate for decision without debate; or he may at his option, in the first instance, submit any such question to a vote of the Members of the Senate. Upon all such questions the vote shall be taken in accordance with the Standing Rules of the Senate.

In President Clinton’s impeachment, for example, Chief Justice Rehnquist, who presided over Clinton’s impeachment, made just one substantive ruling: that those prosecuting the impeachment had to “refrain from referring to the Senators as jurors.”

The Presiding Officer can appoint a separate committee “if the Senate so orders” to actually receive the evidence and testimony under Rule IX, which will subsequently issue a report and transcript to the entire legislative body thereafter. (Though in theory this need not be the case.) This committee structure this was first deployed for the impeachment of District of Nevada Judge Harry E. Claiborne in 1986—the first impeachment trial since 1936—who was impeached after he “was convicted for falsifying his income tax returns and sentenced to two years in prison” (despite planning to return to the bench after serving his time). The separate Senate impeachment committee has been used in most recent impeachment trial since—Judge Alcee Hastings, Judge Walter Nixon, and Judge G. Thomas Porteous, Jr.; in the modern era, the only impeachment trial that did not have such a committee was that of President Clinton. It could certainly be argued that the gravity of the situation—impeaching a President versus impeaching one of 861 potential federal judges (673 district judicial seats, 179 circuit court seats, and 9 on the Highest Court in the Land)—warranted the full Senate rather than a committee.

Who actually “tries” the case is another important question. Giving a brief overview of trial proceedings for the New York Times, Charlie Savage succinctly wrote: “A team of lawmakers from the House, known as managers, play the role of prosecutors.” In President Clinton’s impeachment, 13 House Republicans served as managers. It was, in fact, his role first as a member of the House Judiciary Committee considering the impeachment and then as a manager in the Senate trial that made now-Senator Lindsey Graham a national figure.

The accused, on the other hand, retains private counsel. Clinton famously hired five attorneys—Charles F.C. Ruff, Gregory B. Craig, Cheryl D. Mills, David E. Kendall and Dale Bumpers—to defend him.

How the parties actually advocate for their client is also unique to the impeachment process. First, Rule XXII dictates opening and closing statements:

The case, on each side, shall be opened by one person. The final argument on the merits may be made by two persons on each side (unless otherwise ordered by the Senate upon application for that purpose), and the argument shall be opened and closed on the part of the House of Representatives.

There are also particular rules regarding what questions can be asked and by whom. In this respect, an impeachment trial looks a bit more like a civil law inquisition than a common law trial. Senators submit questions to be answered by one or the other legal party. But there are no Atticus Finch-style courtroom theatrics; indeed, all questions are submitted to the Presiding Officer, who in turn reads them to the parties. (For this reason, Chief Justice Rehnquist once stated that in his capacity as Presiding Officer, “I did nothing in particular, and I did it very well.”)

Witnesses are a different story. Rule XVII and XVIII state that “Witnesses shall be examined by one person on behalf of the party producing them, and then cross-examined by one person on the other side,” and permit Senators to be witnesses, respectively. But that assumes there are witnesses at all. Witnesses are not required for the trial. In fact, at President Clinton’s trial, whether witnesses would be heard at all was in doubt. Eventually, the Senate voted on party lines to compel three witnesses—Monica Lewinsky, Vernon E. Jordan, Jr., and Sidney Blumenthal—via subpoena. Though none gave testimony in an open hearing, all three were deposed in private; the Senate was permitted to view “all or part” of their depositions on tape in a private, secure room. Finally, throughout the entirety of the trial itself, from opening statements to questioning, the Senate must choose which hearings will and will not be public versus private.

After all is said and done, and the trial concludes, Senators vote on each article of impeachment separately—again, just like a jury. As the Constitution mandates, conviction on any article of impeachment needs a two-thirds concurrence.

One of the most important facets of this entire process is that it presents only nonjusticiable political questions. In 1993, articles of impeachment were passed against Walter Nixon—no relation to the 37th President—the former Chief Judge of the U.S. District Court for the Southern District of Mississippi for perjury. The Senate convicted and removed him and Nixon appealed the Senate’s trial procedures. But the Supreme Court concluded it could not review the process:

the use of the word “try” in the first sentence of the Impeachment Trial Clause lacks sufficient precision to afford any judicially manageable standard of review of the Senate’s actions[, which] is fortified by the existence of the three very specific requirements that the Constitution does impose on the Senate when trying impeachments: The Members must be under oath, a two-thirds vote is required to convict, and the Chief Justice presides when the President is tried. These limitations are quite precise, and their nature suggests that the Framers did not intend to impose additional limitations on the form of the Senate proceedings by the use of the word “try” in the first sentence.

Thus, however the Senate resolves to carry out the trial and however the Presiding Officer rules on any objections or motions is all but guaranteed to be final—not because 100 senators are infallible, but because there’s no mechanism to subject their judgment to further review.