The DNA test thus simultaneously gives Trump an obvious way to keep the story going on his terms — just pick the lowest end of the genetic estimate and make sport of a “Pocahontas” who’s only one-1,000th Indian — while also annoying Indian groups and anyone on the left (including the actual minority candidates against whom Warren may run) invested in a vision of affirmative action as a righter of historic wrongs rather than just a means to elite self-congratulation.

Warren should not have taken the test; having taken it, she should not have publicized it; having publicized it, she should quietly fire anyone who urged this gambit and move on. And liberals generally should regard this whole thing as a cautionary tale. There is an obvious appetite on the activist left for a candidate or candidates willing to take on Trump on his own brawler’s terms. But if you come at him that way, you best not miss — as Michael Avenatti, the would-be Trump of the Resistance, has been missing repeatedly of late, with a Kavanaugh intervention that helped get the judge confirmed and a libel lawsuit that just got his own client ordered to pay Trump’s legal fees.

Now Warren has joined Avenatti in that loser’s gallery, for absolutely no good reason that I can see.