Video of the exchange shows Warren pausing to consider her answer. The senator could have begun by acknowledging that the DOJ report was correct and that she was mistaken in calling Brown’s death a murder. Then she could have proceeded to the rest of the story: that the Ferguson police had a pattern of “unlawful bias” against blacks—documented by the Justice Department in a separate report issued on the same day the department cleared Wilson—and that a number of cases, including the deaths of Scott, Garner, and McDonald, underscored the persistent problem of police violence against black men.

Instead, Warren conceded nothing. “What matters,” she told Haslett, “is that a man was shot, an unarmed man, in the middle of the street by police officers and left to die. And I think that’s where our focus should be.”

Warren’s answer compounded her initial falsehood by adding a second myth. As awful as it was that Brown’s body lay in the street for four hours—an affront that even Ferguson’s police chief acknowledged and regretted—it isn’t true that Brown was left to die. (According to the DOJ report on Brown’s death, Wilson’s final shot killed him “where he stood.”) But what’s most concerning is Warren’s failure to admit error, particularly when the error is an accusation of murder. Does she respect facts that don’t fit her narrative? If she becomes the Democratic nominee, will voters see her as a truth teller in the face of Donald Trump’s lies, or as an ideologue? If she becomes president, will she listen to information that complicates her plans? Or will she plow ahead?

Candidates should talk about police bias. They should honor the memory of those whose lives have been taken. There’s no need to rely on a false narrative to tell the truth that black lives matter.