I haven't read the whole article yet, I'll update this comment when I do. But I have a huge problem with they way they set up the premise. You can't assume ”90/10 D/R split" and "voted/didn't" are independent variables. You can't measure mixed nuts by shaking the Brazil nuts to the top and skimming them off.Black voters have consistently supported Democratic candidates over Republicans by stunning margins: about 90 percent to 10 percent. No other major demographic comes close to this level of support — for either party. For every 10 new black voters, 9 will likely vote for a Democrat and one for a Republican, yielding eight net Democratic votes. In contrast, 10 new Latino voters (who voted 70 percent Democratic and 30 percent Republican in 2018) would produce four net Democratic votes. For white, college-educated women, the figure is two.