Mike Blake / Reuters

No president of the United States has ever been prosecuted. Richard Nixon, who likely came the closest, was rescued from the threat of criminal charges by a pardon bestowed by his successor, Gerald Ford. But now, in the wake of the Mueller report’s account of potential obstruction of justice by President Donald Trump, Democratic politicians are beginning to weigh the possibility that Trump will be brought before a court.

“I want to see him in prison,” Speaker of the House Nancy Pelosi reportedly told House Democrats in a closed-door meeting earlier this month. And asked by the NPR reporter Scott Detrow whether, as president, she would support bringing an obstruction case against Trump, the Democratic presidential candidate Senator Kamala Harris answered: “I believe that [the Department of Justice] would have no choice and that they should, yes.”

Harris framed her answer in the language of justice: “Everyone should be held accountable, and the president is not above the law.” Yet her comments should be concerning to anyone who cares about maintaining the independence of law enforcement from political influence.

The idea that a presidential candidate can permissibly endorse the potential prosecution of a political opponent is itself a sign of how much damage Trump has done to that principle. Part of that damage comes from Trump’s own insistence on treating the Justice Department as a personal political tool, which eats away at the codes of behavior that have, in the past, barred politicians from making similar promises. Part of it also comes from the strain Trump has put on the constitutional system. Trump’s conduct is what has forced these questions on presidential candidates and political leaders: What, after all, do you do with a possibly criminal ex-president? What does it mean to balance accountability against the importance of preserving an apolitical system of law? How, in the wake of the Trump presidency, are Americans to understand what “justice” means?

Trump has long enjoyed calling for the prosecution of his enemies; “Lock her up!” was a favored mantra during his 2016 campaign against Hillary Clinton. He has demanded that investigations be launched into and charges be filed against Clinton and others, including former FBI Director James Comey. According to the evidence set out by Special Counsel Robert Mueller, these are not idle musings: Trump privately demanded several times that the Justice Department “look into” his opponents, at one point calling then–Attorney General Jeff Sessions at home to ask that the department investigate Clinton. When Sessions did not oblige, Trump began attacking him publicly for his failure to do so.

Harris’s statement, and to a lesser extent Pelosi’s, is a long, long way from “Lock her up!” But it is also a lot closer to that promise than anyone should be comfortable with. In a liberal democracy, the government is constrained by a network of rules, such as the presumption of innocence, that limits the deployment of power. Trump’s own efforts to use the Justice Department to go after those he dislikes have provided us with a vivid demonstration of the importance of independent law enforcement. Nothing good will come of a system in which the chief executive may direct the full force of the state against those he believes have wronged him. And nothing good will come of a political candidate running for high office on the suggestion that her administration would prosecute a particular individual. As if to emphasize the norm-breaking aspect of Harris’s statement, Trump commented in an ABC interview that “probably, if I were in her position,” he would have said the same.

The delphic language of the Mueller report forced Democratic candidates to grapple with this issue. Mueller did not reach a conclusion on whether the evidence would support a charge of obstruction of justice against Trump, because, he wrote, a Justice Department memo precluding the indictment of a sitting president barred the special counsel’s office from doing so. Yet he also noted that “a President does not have immunity after he leaves office”—and in part because of this, the office “conducted a thorough factual investigation in order to preserve the evidence.”

Mueller’s implication was that future prosecutors may be able to turn to the record preserved by the report in evaluating a possible prosecution of citizen Trump. So presidential candidates weighing how to handle hypothetical charges against Trump are, in some sense, picking up a question that Mueller left on the table. This is different from Trump’s own promise to “lock [Clinton] up” on the basis of conduct that, according to Comey, would have left “no reasonable prosecutor” able to bring a case—not to mention Trump’s insistence that Comey and others should be charged for behavior that is not criminal at all.

Harris gave the wrong answer, and Pelosi should not have said what she did. But Mueller’s invitation raises a series of issues that are not easily resolved. The question of how to handle potential criminal charges against Trump after he leaves office is actually several questions: First, should a presidential candidate weigh in on the matter? (Arguably no, as my Lawfare colleague Benjamin Wittes has written.) Second, should a future Justice Department consider bringing charges against Trump at all? It is, after all, not the president but the attorney general who would supervise the department in making that decision and evaluating the evidence—and it is the independence of that prosecutorial judgment that has come under attack during the Trump presidency.

This leads to the third question: To what extent should a future president be involved in the Justice Department process leading to that determination? And, finally, should the president let a potential prosecution go forward? In his pardon of Nixon, which precluded any indictment by the special prosecutor’s office, Ford argued that a trial of a former president would risk destroying “the tranquility to which this nation has been restored” after the bitterness of Watergate.

These are complicated issues, not least because they force, once again, a confrontation with the puzzle that Trump has repeatedly posed: While independent law enforcement is a foundation of the American constitutional system, the Justice Department is nevertheless under the direct control of the president, who has the power to intervene in an investigation or prosecution if he so chooses. So does the president exist above or outside the law? Is producing accountability possible in a system under which a sitting president may not, in the understanding of the Justice Department, be subject to prosecution by the law-enforcement apparatus he oversees?

“There is an important national interest in ensuring that no person—even the President—is above the law,” reads the 2000 Justice Department memo enshrining the principle that a sitting president may not be indicted. But the memo goes on, “Recognizing an immunity from prosecution for a sitting President would not preclude such prosecution once the President’s term is over or he is otherwise removed from office by resignation or impeachment.”

Any presidential campaign is an effort to will into existence a possible future. Usually, this imagined future is simpler than the one that will actually come into existence, and so far the Democratic candidates have largely sought to use their campaigns to imagine a post-Trump future wiped clean of the current president’s legacy. But the question of how to handle a potential prosecution of Trump zeroes in on the ugly, difficult aspects of rebuilding American democracy.

The best way to understand what America will be after Trump is to envision it as a post-conflict society in need of reconstruction—and like other post-conflict societies, there will be hard decisions to be made about how to square the need for accountability and justice with the necessity of healing, and how to balance justice with accountability when the two do not always coincide. South Africa, for example, offered immunity from prosecution to perpetrators of apartheid violence in exchange for truthful public testimony about the abuses they had committed.

In “Federalist No. 74,” Alexander Hamilton describes the pardon power as not only a manifestation of mercy but also a political tool to be used in moving a society forward after conflict: “In seasons of insurrection or rebellion, there are often critical moments, when a well-timed offer of pardon to the insurgents or rebels may restore the tranquillity of the commonwealth.” Ford pointed to this understanding of clemency in defending his pardon of Nixon before the House of Representatives.

The next president, whoever he or she may be, may not reach the same decision as Nixon’s successor, but he or she is going to need to weigh the same problems that Ford considered with care and seriousness. How can the country best hold Trump accountable for the wrongdoing described in the Mueller report and placed on display throughout his presidency? Even if criminal charges are merited, are they the best way to achieve this goal? How great is the risk that any such prosecution magnifies perceptions of law enforcement as a political tool, and so further eats away at public faith in the legitimacy of the government? Is that risk nevertheless worth running?

The hitch, of course, is that the 2020 campaign requires the country to confront these questions about what things will look like after the end of a Trump presidency while it is still very much in the midst of that presidency’s chaos. And any eventual consideration of prosecution will be inflected by how the House of Representatives chooses to play its cards: The Justice Department memo, after all, points to impeachment as a mechanism of holding a criminal president accountable, distinct from prosecution while in office.

Although Pelosi has suggested that a possible prosecution later would render moot any impeachment now, there is no reason that this should be the case. Democratic presidential candidates are considering what they might do in the future to hold Trump accountable. But the House must also ask itself what it will do right now.

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