There is no legal bar to President Donald Trump being indicted if he leaves office in January 2021, but that does not mean that Congress or the American people should rely on the criminal justice system to police presidential misconduct. When the practical impediments and prudential considerations that could stand in the way of prosecuting a former president are factored in, the chances that Trump will face criminal consequences for his actions could, in fact, be quite slim. These considerations counsel strongly in favor of the House of Representatives proceeding with a full impeachment inquiry of the president. Failure to do so could risk an outcome that is repugnant to constitutional democracy: a president who has engaged in multiple episodes of potentially criminal and impeachable conduct may never face a formal accusation of wrongdoing.

If there is one lesson to draw from Special Counsel Robert Mueller’s report and congressional testimony, it is not that the president has been exonerated. Mueller compiled compelling evidence that the president engaged in conduct that likely could have been charged as obstruction of justice or witness tampering. However, the special counsel did not consider whether Trump should be indicted for obstructing the Russia investigation because he was bound by Department of Justice policy stating that a sitting president cannot be indicted. Similar calculations reportedly factored into the decision by federal prosecutors in New York to close an investigation into potential campaign finance crimes and related offenses that directly implicated the president. In that case, the publicly available evidence also does not exonerate the president. Instead, there is compelling evidence that the president personally committed up to eight federal criminal offenses while participating in and covering up a scheme to suppress negative stories about him from impacting the 2016 election.

The Justice Department’s policy that a sitting president cannot be indicted rests on the assertion that prosecuting a president would so impair his ability to perform the duties of his office that it would amount to an unconstitutional violation of the separation of powers. To be clear, the courts have not gone that far. In previous instances where sitting Presidents Richard Nixon and Bill Clinton challenged whether they could be forced to participate in civil litigation or grand jury proceedings, courts have acknowledged that while sitting presidents must be afforded special accommodations, they are not immune from federal or state judicial proceedings. There are good reasons for subjecting a sitting president to the jurisdiction of the courts. One is that granting a president full immunity could also violate the separation of powers by undermining the courts’ constitutional authority to hear and try criminal cases. Another is that if Congress is disinclined to impeach a president for serious misconduct, the judiciary could be the sole forum in which a president can be held accountable to the rule of law.

Even if there are reasons to question the legitimacy of DOJ’s policy, it is unlikely to change anytime soon. Instead, it’s more important to focus on the policy’s most significant limitation and when it is lifted: whatever protection from prosecution a sitting president enjoys comes to an end when he or she leaves office. That makes the president’s circumstances very different from cases where DOJ is bound to a decision not to prosecute. When a prosecutor grants a witness immunity in exchange for her cooperation and testimony, or when a prosecutor agrees not to prosecute a company in exchange for factual admissions and promises to take corrective actions, the government is bound by that agreement as long as the potential defendant holds up her or its end of the bargain. That is not so for an individual who no longer holds the public office that DOJ deems to be constitutionally protected from prosecution.

Attorney General Bill Barr’s conclusion that the evidence compiled by Mueller is insufficient to prosecute the president for obstruction of justice would not be binding on a future administration. Indeed, DOJ made this very point in a recent court filing. “[I]n all cases in which prosecution is not otherwise barred,” DOJ asserted, “the Department is not precluded from bringing such charges in the future, were evidence developed that supported the principles of federal prosecution governing the standards for initiating criminal prosecution.” (Citizens for Responsibility and Ethics in Washington, the nonpartisan ethics watchdog I work for, has filed an amicus brief in this litigation.)

Not only is Barr’s determination not binding, a subsequent attorney general or prosecutor would be justified in reaching a different decision. A side-by-side comparison of the statements from Barr and Mueller reveal near complete contradictions on the law of obstruction and the evidence against the president. It should also not be forgotten that Barr has engaged in a pattern of conduct that calls into question his objectivity on criminal matters that implicate the president. That conduct includes Barr’s drafting, prior to his nomination, an unsolicited 19-page memo to Deputy Attorney General Rod Rosenstein (who oversaw Mueller’s investigation at the time), arguing that the investigation into the president’s obstruction of justice was premised on a “novel and legally insupportable reading of the law.” Barr’s decision that the evidence of obstruction is insufficient does not reflect an accurate understanding of the law or the evidence, and even if it did, his decision would not bind his successor.

Instead, the most important potential obstacle to reversing course on prosecuting the president is the statute of limitations, which precludes the prosecution of offenses after a certain amount of time has elapsed. If Trump left office in January 2021, the five-year statute of limitations applicable to the crimes in question will not have expired on any conduct that occurred after January 2016. That means that the president could still be prosecuted for potential crimes committed in the scheme to commit and conceal campaign finance violations or the president’s obstruction of the Russia investigation.

The statutes-of-limitation analysis gets more complicated if you assume Trump wins a second term. By January 2025, the default statute of limitations will have run on the president’s apparent campaign finance violations and episodes of obstructing justice because they occurred prior to January 2021. But that wouldn’t necessarily preclude him from being prosecuted: part of DOJ’s justification for its policy of not indicting a sitting president is that a court could “toll” (suspend) the statute of limitations while a president is in office and therefore permit his prosecution after he leaves office. There is a strong rationale for “equitable tolling” in these circumstances–we would avoid a regime in which the president can violate criminal laws with impunity–but the precedent for its application is hardly ironclad.

Assuming the statute of limitations either hasn’t expired or is tolled, the most significant obstacles to prosecuting Trump after he leaves office are practical and prudential. Several of these obstacles are mentioned in a remarkable memorandum that aides to Special Prosecutor Leon Jaworski penned on the day that Nixon resigned. The piece begins from the premise that “Nixon should be indicted and prosecuted” because of a “presumption (which in the past we have operated upon), that Richard M. Nixon, like every citizen, is subject to the rule of law,” and goes on to list five factors mandating against prosecution and five mandating in favor of it.

Some of the factors mandating against indictment of Nixon are–at least for the moment–not applicable to Trump. Resignation was a form of punishment that Nixon experienced but that Trump seems unlikely to. Nixon was subjected to an impeachment inquiry that resulted in the endorsement of articles of impeachment by the House Judiciary Committee, but Trump has yet to be formally accused of wrongdoing. The other three factors are harder to distinguish. The arguments that “[p]rosecution might aggravate political divisions in the country,” that “the times call for conciliation rather than recrimination,” and that “[t]here would be a considerable difficulty in achieving a fair trial because of massive pre-trial publicity” could hold as true in Trump’s case as they were in Nixon’s.

Nevertheless, Jaworski apparently felt compelled to prosecute Nixon after also considering the five factors that weighed in favor of prosecution: the principle of equal justice under the law; the need for final disposition of charges of criminality outstanding against Nixon “to forestall the belief that he was driven from his office by the erosion of his political base” and “to preserve the integrity of the criminal justice system and legislative process”; the fact that the Constitution explicitly states that impeachment and removal from office does not provide immunity from subsequent criminal prosecution; the inadequacy of removal from office as a punishment for criminal offenses; and the unacceptable precedent of appearing to immunize “all future Presidents for their actions, however criminal.” These factors could of course tip the scales in favor of prosecuting Trump after he leaves office.

Nixon’s story, as we all know, did not end with his indictment and trial. Instead, his successor, President Gerald Ford, issued a controversial pardon to the former president–a precedent that would be complicated to apply in Trump’s case. A president considering executive clemency has even broader considerations to weigh than a prosecutor, especially if we imagine that Trump’s successor would be a political rival rather than an ally.

On the one hand, there would be a tremendous irony to Trump’s successor absolving him of criminal liability since Trump shattered long-established norms by calling for his 2016 opponent to be jailed and later asking his attorney general to prosecute her. But there are also reasons to think that exercising forbearance might be the best way to repair the norms that Trump has so callously flouted. On the other hand, if Trump continues to escape formal accusations of wrongdoing, Nixon is an imperfect analogue, for he was named in an indictment as an unindicted coconspirator and formally accused of impeachable conduct by the House Judiciary Committee. A pardon of Trump that preempted his official condemnation would set a terrible precedent for our democracy.

Which brings us back to impeachment. Impeachment inquiries and criminal prosecutions have different processes, standards, and purposes, but when applied to a president, they share a common purpose: policing the bounds of acceptable executive branch conduct. In a world where indicting a sitting president is not possible and prosecuting him after he leaves office raises practical and prudential concerns, impeachment could very well be the only way for our polity to express repugnance for the president’s actions. To shrink from that responsibility and hope that Trump will face criminal prosecution at some later date is to risk inviting his successors to flout the law with impunity, safe in the knowledge that no one is above the law–except the president.

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