Senate candidate Elizabeth Warren was proud to be a Native American prior to her hiring at Harvard Law School in the mid 90's. After that, she mysteriously stopped listing herself as a minority in the Association of American Law Schools desk book.
I have no doubt she retained her pride in her ethnic status (whatever it was), but having ridden the Affirmative Action train to the end of the line at Harvard Law she wanted to avoid any taint of being an affirmative action hire. Just a guess, obviously - I don't want to be defaming someone with a legal background.
Jim Geraghty has more. I believe it was David Bernstein who first cracked open the old AALS directories (although an intrepid reporter may have moved independently) and he has informed speculation as well.
For my money, Ms. Warren is one more liberal who will defend Affirmative Action passionately, will pooh-pooh the notion of an Affirmative Action stigma, and will deny that Affirmative Action played any role in her own advancement. Whether this costs her votes in Massachusetts, where the Irish do not benefit from Affirmative Action, remains to be seen.