Sure they have: Elizabeth Warren AKA Lieawatha and Fauxcahontas.............
Perhaps, but I think they know she can't win. It may be, as I have speculated before, that the Dems actually want to lose in 2016, so that when the SHTF it can be blamed on the GOP in general and "ultra-right-wing conservatives" in particular, and someone like Warren or Julian Castro can fly into DC in their Superperson cape and complete the Fundamental Transformation that Obama has put in place. The only bee in the buttermilk is that it is possible for a true conservative to actually handle the SHtingTF and revive Morning in America, a la Reagan in 1980-84.