In recent decades, Congress – and more specifically, the House of Representatives – has tended to rely on others to prepare the way for an impeachment inquiry. Famously, the House moved against President Bill Clinton only after an extended investigation by independent counsel Ken Starr. At times, Congress has waited so long to impeach that its target is already imprisoned, as in the case of Judge Harry E. Claiborne. Most recently, in the case of Judge G. Thomas Porteous, Jr., Congress acted on charges of bribery and perjury and impeached, convicted, and removed the judge from the bench—but only after the Department of Justice had pursued a criminal investigation, and after the United States Court of Appeals for the Fifth Circuit had conducted its own inquiry and found Porteous guilty of judicial misconduct.

That Congress seems to prefer outsourcing the impeachment power is not entirely surprising.  Legislative time is valuable, and pursuing an impeachment inquiry is time-consuming and distracting. The political payoff from pursuing an impeachment is not generally very obvious or certain, and legislators might reasonably think their energies are better invested in more rewarding activities like lawmaking or constituent service. And impeachments are (fortunately) not common, so legislators are unfamiliar with the process.

But relying so heavily on prosecutors to develop the underlying charges supporting impeachment has come at a high cost.

Impeachable Actions Need Not Be Criminal Offenses

Prosecutors investigate criminal offenses. They are concerned with violations of the criminal law and the evidence needed to demonstrate those violations. That is a useful and sometimes necessary task, but congressional reliance on criminal investigations has the effect of flattening the scope of the impeachment power. Indeed, it has created the widespread impression that the impeachment power can only appropriately be used when criminal offenses have been proven. This devalues the ultimate political purpose of the impeachment power.

The standard that the Constitution identifies to justify an impeachment is laid out in Article II, Section 4: “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.” There is no question at present of treason or bribery, so the relevant standard is “other high Crimes and Misdemeanors.” This is not a legal term of art. There was no well-worked-out law in 1787 specifying the meaning of high crimes and misdemeanors, and the relatively few cases of impeachment that have been considered by Congress since the nation’s founding have not comprehensively fleshed out the meaning of those terms. But the phrase is not meaningless.

The impeachment power was sewn into the fabric of the Constitution in order to provide a check against abuses by government officials. It was not intended to empower Congress to remove an officer who is simply unfit or generally incompetent, and it would seem to be particularly unwise for Congress to assume a power to overturn the people’s judgment on the general fitness or policy acumen of an elected president. Impeachment is a remedy for abuses of public office. It allows Congress to respond to conduct of the president if such abuses pose a grave and immediate danger to the country and cannot be allowed to fester until the next presidential election that would allow the people themselves to resolve the problem.

But what counts as abuses that are sufficiently grave to warrant an impeachment? The constitutional responsibility entrusted to Congress to make such assessments is intentionally flexible. The founders did not limit impeachments to criminal offenses or even necessarily to public misconduct. They did not try to anticipate all the ways that a future president might abuse the high duties of his office and render himself unfit to continue in office. Still, it is clear that the impeachment power was intended only to be used in exceptional circumstances.

It remains to be seen whether special counsel Robert Mueller’s investigation will uncover evidence of serious crimes, and there is good reason to doubt that some of the most controversial actions taken by the president could properly be held accountable under the criminal law. That does not mean, though, that there is nothing for Congress to worry about. In fact, the table is already set for Congress to make its own inquiries into the behavior of the president and others in and around the administration, with an eye to possible impeachment.

Impeding the Investigation of Russian Meddling

The president has moved from crisis to crisis, and they are all of his own making. These are forgivable errors that could be corrected, and some of them might have been expected of a political novice with few experienced political advisors. The pattern of the president’s missteps, however, cannot be readily ignored, as they have reached a point that can no longer be chalked up to mere inexperience.

The president of the United States has a particular obligation to uphold the rule of law. Only the president takes an oath to defend the Constitution and faithfully execute his office, and only the president is entrusted with the power—as well as the duty—to see that the laws are faithfully executed. These obligations and responsibilities sometimes require that the president exercise discretion and make difficult decisions about priorities and about how best to effectuate the laws of the United States, but they also impose a particular burden on the president to make sure that in both appearance and action, the laws are being equally applied to all and without favor to anyone—including the president himself and his associates.

With this in mind, President Trump stepped on a land mine by firing FBI director James Comey and admitting that he was motivated to do so by a concern with Comey’s investigation into Russian meddling with the American elections in 2016. Regardless of whether Comey’s removal can be prosecuted as obstruction of justice, there is little question that in this case, the president exercised his constitutional powers in a self-serving manner rather than one that is even superficially consistent with the national interest.

Fortunately for the president, impeachment is not the only available tool for addressing Comey’s removal, and Mueller’s appointment as special counsel ensured that the investigation would continue without undue interference from the White House. The president’s public comments since Mueller’s appointment, however, make it clear that Trump is tempted to remove Mueller as well, or at least to direct Justice Department officials to do so. He currently seems intent on trying to drive Attorney General Jeff Sessions from office, presumably with the goal of replacing him with someone more willing to interfere in the Russia investigation, having publicly complained that Sessions should not have recused himself from that investigation.

The removal of Mueller should be a red line for Congress in a way that the removal of Comey was not. Removing Mueller at this juncture would make it clear that the president’s intransigence about the Russia investigation cannot be remedied by anything short of removing him from office. The granting of a pardon to himself or close associates for any criminal acts committed during or since the presidential campaign would raise similar issues.

In short, an impeachment of the president would be justified if it were necessary to sustain the rule of law against self-aggrandizement by occupants of the White House. For purposes of impeachment, the correct question is not whether the president engaged in an indictable crime of obstruction of justice. The question is whether he exploited the powers of his office in a manner that is inconsistent with his constitutional duties, and thus with the rule of law.

The Emoluments Controversy

The ongoing controversy over whether the president is in violation of the foreign emoluments clause of the Constitution poses more difficult issues. The clause in Article I, Section 9 states that “no Person holding any Office of Profit or Trust [in the federal government] shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State.” The question of what constitutes an emolument is not itself entirely new, but Trump’s financial circumstances are fairly unique.

As a result, there are two distinct challenges for those who might want to hold President Trump to account for the violation of this clause. First, the president’s finances are not transparent. Before we could know whether or not the president has an emoluments problem, we would need to access his financial records. There may be reasons to launch such a factual inquiry, but we are far removed from knowing the results of it. Second, there is no general agreement on what the emoluments clause requires in these circumstances, precisely because the issues created by Trump’s ascension to the presidency with his sprawling business empire intact, and under his family’s direct control, appear to be sui generis.

If so, the most immediate need might simply be to identify and contain any apparent conflicts of interest, if that is possible, without necessarily reaching consensus on the requirements of the emoluments clause itself. In addition, if we think the Trump presidency is representative of longer-term problems, then it would be fruitful to lay down clear markers on expectations regarding the business affairs of future presidents. (The example of the Twenty-Second Amendment, which limited the president to two terms shortly after the death of FDR, might suggest that it would be easier to reach agreement on the implications of the emoluments clause if we looked ahead rather than trying to apply it to the incumbent.)

Congress seems the most suitable institution for evaluating and remedying possible violations of the emoluments clause, but apparent lack of interest in the issue on the part of Congress has spurred court filings in an attempt to force action. If the current majority in Congress does not rouse itself to take the question of the president’s financial conflicts seriously, then it may find the matter taken out of its hands.

The Question of Classified Intelligence

The news that the president may have revealed classified intelligence sources to Russian government officials is itself sufficient to justify a congressional impeachment inquiry. An inquiry would establish whether such a disclosure took place and would reveal the factual circumstances surrounding it. If the president revealed such information to a hostile foreign power without a larger strategic objective and without the advice of relevant national security officials and foreign allies, then the House would be justified in considering impeachment charges.

The question is not whether the president revealed information that he, as commander-in-chief, is legally permitted to reveal. The question is whether he acted in a manner consistent with his oath of office and his duties under Article II to “faithfully execute the Office of President of the United States” and “preserve, protect and defend the Constitution of the United States.” If the president, through wanton carelessness or severe misjudgment, undermined American national security, not by making a controversial decision on public policy, but by mishandling the nation’s most sensitive intelligence, then he abused his office in a manner that the Constitution empowered Congress to remedy through impeachment. Congress cannot undo the damage the president has already done, but the impeachment power is designed to address a situation in which an officeholder has demonstrated through his past actions that he can no longer act in the public trust.

Disagreeable policies, incompetent management, and evident character flaws are the familiar concerns of electoral campaigns. The people are entitled to elect officials whom some might regard as fools or knaves. That is their prerogative in a constitutional republic. But when those officials engage in gross misconduct and forfeit the great trust that was placed in them by the people, then the people’s representatives, assembled in the national legislature, have a responsibility to take action of their own. When a long train of abuses and usurpations demonstrates that an official can no longer be trusted to exercise his constitutional office in good faith, then resort to impeachment and removal is proper and may be necessary.

Keith E. Whittington is the William Nelson Cromwell Professor of Politics at Princeton University and author of Constitutional Construction: Divided Powers and Constitutional Meaning.