Of all the lunatic gestures with which one expected prospective Democratic 2020 hopefuls to try to distinguish themselves in a crowded field, Massachusetts Sen. Elizabeth Warren's mini-documentary about her Cherokee ancestry is among the most improbable. It is certainly going to be the most embarrassing.

President Trump has long seized on Warren's past claims of Cherokee ancestry to mock her. For nearly a decade, the Association of American Law Schools identified her as a racial minority, apparently on the basis of something Warren's grandmother had told her. In response to critics of the faculty's racial homogeneity, Harvard Law School, where Warren was a law professor, described her as a woman of color for more than half a decade. While there is no evidence to suggest that her claims about her racial identity have had any serious bearing upon her professional career, critics such as Trump and then-Sen. Scott Brown, Warren's Republican opponent in the 2012 Massachusetts Senate race, have demanded that she "prove" her Native American heritage. In the years since this 2012 race, Trump has repeatedly referred to Warren as "Pocahontas." This is supposed to be amusing because the daughter of the Powhatan chief who married John Rolfe was also a female indigenous American.

In the above video, released Monday to a chorus of howling mockery, Warren is now touting the results of a DNA test that provides "strong evidence" that between six and 10 generations ago — i.e., in the early 19th century — a single member of her family was Native American. The Boston Globe described her decision to share the results of the test as "an unprecedented move by one of the top possible contenders for the 2020 Democratic nomination for president." That's certainly one way of putting it.

Why did Warren think this was a good idea? The whole saga is something that she would have done better to put behind her. Trying to answer Trump's bullying with a sub-Politifact level #actually is misguided to say the least. Does she really think he is going to apologize because she took a blood test — or for any other reason? Warren's investment in the veracity of a bit of old family lore makes her look as silly as the president. Her insistence that he now make good on his off-hand promise to hand over $1 million now that she's taken a DNA test makes her look delusional. It is a masterclass in how Democrats ought not to respond to the president.

But there are more serious reasons than message discipline to push back against this kind of nonsense. The attempt to define membership in a community on the basis of a small amount of genetic data seems cheapening to say the least. One would expect a progressive like Warren to be aware of the poverty, crime, and addiction on Indian reservations in her home state of Oklahoma and elsewhere. Warren's resilience in the face of other hardships make her professional and political success admirable in its own right, but the brutalization of the American Indian is one of the great crimes of history. For a woman who has not shared in their plight to claim Native American ancestry seems to me a kind of stolen valor. Doubling down on it in response to schoolyard taunts exacerbates the problem.

More worrying still, Warren's response also harkens back, no doubt unintentionally, to the era of the so-called "one-drop rule," according to which a man or a woman would be considered black under law if he or she had even a single remote ancestor of African descent. At a time when "scientific" racism sees to be making a comeback in some right-wing circles, the last thing this country needs is a national conversation about race that hinges upon the binary question of whether a person with one untraceable antecedent who was not Caucasian should really be considered white or something — anything — else.

Warren is wasting her own time, that of her supporters, and that of the American people, to say nothing of making a mockery of the suffering of Native Americans, in an attempt to respond to a silly jibe. If she is really the level-headed pragmatist she has presented herself as in other contexts, she would have ignored Trump and talked about things that matter — like the record of this administration and her plans to help working- and middle-class Americans — instead.