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.