Kamala Harris taught a master class this week in how not to address the question of accountability for President Trump, declaring to the NPR Politics Podcast that she favors Trump’s indictment and prosecution after he leaves office. Asked if she believes prosecutors should bring a case against Trump, Harris said, “I believe that they would have no choice and that they should, yes."

“There has to be accountability,” she elaborated:

I mean look, people might, you know, question why I became a prosecutor. Well, I'll tell you one of the reasons—I believe there should be accountability. Everyone should be held accountable, and the president is not above the law. The facts and the evidence will take the process where it leads, but I have read the Mueller report. I do believe that we should believe Bob Mueller when he tells us essentially that the only reason an indictment was not returned is because of a memo in the Department of Justice that suggests you cannot indict a sitting president. But I’ve seen prosecution of cases on much less evidence.

She refrained from chanting, “Lock Him Up!”—for which I suppose we should be grateful.

Harris is not the only prominent Democrat to have dipped her toes in these dangerous waters. Speaker of the House Nancy Pelosi reportedly said recently that she didn’t want to see Trump impeached, she wanted to see him jailed. We can expect others to weigh in over the coming weeks as well.

Paul Rosenzweig is fond of saying that you don’t protect norms by violating norms. And with the president so flagrantly and consistently abusing basic expectations regarding the nonpoliticization of law enforcement, it is tempting to be tolerant when Democrats—or Republicans, for that matter—return the favor in some small measure. But declaring someone guilty of crimes, as Pelosi reportedly did, and saying that as president you would supervise that person’s prosecution, as Harris did, is poisonous stuff in a democracy that cares about apolitical law enforcement. It’s poisonous to a society that believes in a presumption of innocence. It’s poisonous to a society that believes in limiting the relationship between political actors—including the president—and the deployment of the coercive powers of the state against individuals. A presidential candidate’s promising a law enforcement outcome against an individual should be unacceptable—even to those who fervently wish to see Trump in the defendant’s chair in federal court.

The hard question is not whether Harris gave a bad answer to NPR’s question. She did. The hard question is what answer she should have given—and how other candidates should handle similar questions in the future if they want to honor the norms of apolitical law enforcement.

Reporter Scott Detrow asked Harris: “I want to ask you about a possible future prosecutorial decision. Whether or not you are in the room, you would be appointing the people who would be in the room. You ended that recent speech talking about the 10 counts of obstruction of justice ... in the Mueller report …. But of course, as Robert Mueller said, there is that current DOJ policy that you can’t charge a sitting president. You have been very clear that you want impeachment proceedings to begin. If you become president, if he was never impeached, would you want the Department of Justice, now that he is no longer a sitting president, to go forward with those obstruction of justice charges?”

The question is hard because it actually contains a number of subsidiary questions. There is, first, the question of whom one would pick as attorney general and what understanding—if any—would one have with that person regarding how to handle the obstruction questions raised by the Mueller report. The president, after all, doesn’t seek indictments. As Detrow’s question reflects, the president chooses an attorney general, who supervises the Justice Department, and the department seeks indictments. So the question “would you want the Department of Justice” to do something translates, in the first instance, to the question of whether you would appoint an attorney general whom you believe would do that thing.

Second, there is the question of whether and to what extent the president would then be involved in the attorney general’s decision as to how to proceed. In other words, having appointed Person X as attorney general, to what extent would you tell Person X what you want to happen and to what extent would you consider that choice to be Person X’s call to make?

And then there is the pardon question: The power the president actually has here is the power to make a case go away directly, either before or after it is filed. If a president does not want to allow the prosecution of his or her predecessor, directing the attorney general not to bring such a case is only one way to bring about that outcome. The other way is the way Gerald Ford did it: pardoning Richard Nixon before the special prosecutor could bring an indictment against him. So embedded in the should-Trump-be-prosecuted question is the would-you-pardon-Trump question—a question Harris’s fellow Democratic presidential candidate Pete Buttigieg struggled with in a recent conversation with the Washington Post.

Complicating these questions are a number of additional factors. The Justice Department has a strong norm against one administration reopening criminal matters the previous one has closed—though that norm has important exceptions. Moreover, the country has a deep tradition of administrations not prosecuting their predecessors; it’s part of that whole peaceful transition of power thing.

On the other hand, Special Counsel Robert Mueller never performed what he termed a traditional prosecutorial analysis of the evidence of obstruction, and Attorney General William Barr’s own analysis was quick and came off to many analysts (including me) as highly political. So it’s a really difficult question whether the next attorney general should regard it as a final prosecutorial judgment—and it’s probably an unanswerable question without seeing the work product that underlies Barr’s determination.

Finally, there are important things we don’t know that could reasonably bear on the question of Trump’s possible prosecution. Perhaps the most important of these is Trump’s behavior between now and when the question ripens. The matter will look very different if he, say, loses in a landslide and leaves office graciously (for him) than it will if he loses narrowly, refuses to accept the results of the election, and resists leaving office. One important prudential factor in the question of his prosecution, after all, might reasonably be the extent to which criminal process against the former president would serve to protect against an ongoing threat to democracy—rather than, say, merely serve as retroactive accountability for past conduct.

Put all this together, and it’s hard to think of a simple answer to Detrow’s question that honors all of the various principles of which an aspiring president needs to be cognizant. The candidate cannot say anything that promises either to direct or encourage Trump’s prosecution or to prevent it. Any such promise, in either direction, involves a statement of political direction to law enforcement on a specific investigative matter of the type that must be anathema.

The candidate can and should promise to pick an attorney general in whom the public can repose confidence and to defer to the Justice Department on investigative matters, in general—but it’s very important neither to seek nor to suggest that one will seek any kind of understanding with the attorney general as to how he or she will behave.

A presidential candidate should also neither promise to use nor promise not to use the pardon power with respect to Trump. Circumstances might reasonably call for either course, and it’s important to maintain flexibility on the subject for now.

Candidates should also avoid doing prospective damage to the tradition of presidential administrations not going after their predecessors. Normalizing this sort of rhetoric is extremely dangerous.

For all of which reasons, I think the best way for a candidate to answer Detrow’s question is to forthrightly and candidly refuse to answer—and to explain why.

Here is what I wish Harris had said: “My view of the relationship between the White House and the Justice Department does not allow me to answer that question, which raises important issues related to the peaceful transition of power, the finality of Justice Department decisions to close cases and the presumption of innocence. I would select an attorney general the public can trust to handle delicate investigative and prosecutorial questions, and I would make sure that person has the latitude to do his or her job without political interference—including from me. I am also aware that the only prior time such an issue has arisen in our history, it was resolved not by Justice Department action but by presidential action. So as to preserve my own latitude for independent action, I think the less I say on the subject, the better.”

Such a statement wouldn’t light a fire in the hearts of any political constituency, but it’s the right answer.