I suppose it was inevitable that, when the results came back from North Carolina and Indiana, people would begin calling for Clinton to drop out of the race. I don't think she should.
I'm not going to appeal to the most obvious reason, which is that many of the superdelegates still remain uncommitted. (In the DNP, it really ain't over til it's over.) Although superdelegates are not bound by rule to vote for any particular candidate, I would be shocked if they overturned the popular will. (That said, I've been shocked before.) Nor do I really think that Clinton has a chance of winning the Democratic nomination at this point. (Because I can do math.) Rather, I think that her presence in the race is a necessary reminder of how far the "left" still needs to go in this country.
I must admit, if you had asked me two years ago which was more likely--a famale Presidential candidate or a black Presidential candidate--I would not have even hesitated to say that Americans would elect a woman before they/we would elect an African-American. That misjudgment on my part was strangely paralleled by my teaching experience this past academic year. In the Fall semester, I taught a course on Philosophy and Race (in Memphis), which I expected to be a bit of an uphill battle. Although the students were definitely challenged and sometimes resistant (especially on the subject of white privilege), I still found that, on the whole, they were fairly well equipped with both a vocabulary and an arsenal of concepts for talking about race. This past semester, I taught Feminist Philosophy, which was a horse of a completely different color (or, I suppose, gender). My experience was that students still struggle mightily with what are at this point decades-old stereotypes of females and feminism, and when pressed, most of them uncritically revert to biological essentialism to justify their values and evaluations. Perhaps most shockingly, I found that there is not the same sort of social sanction attached to being openly misogynist (or homophobic) as there is to being openly racist. And, further, I would say that this past primary season has demonstrated the same phenomena writ large.
I would definitely classify myself as an "ABB" ("Anything But Bush") Democrat, which means that I would have happily voted for either Clinton or Obama (or Edwards). After John Edwards dropped out of the race, I began to lean more towards Obama mostly in defiance of the 20-year Clinton/Bush White House dynasty. So, my support for Obama is less a direct rejection of Hillary Clinton than it is an objection to certain symbolic/structural trends in American politics over the last couple of decades. However, I have been deeply disappointed (and disturbed) by the anti-Clinton rhetoric coming out of the Obama camp, which tends to rely on a conflation of Hillary Clinton with her husband (as if Hillary really is the "second sex") and grossly reductionist, sexist stereotyping. One would think that supporters of an African-American candidate for President, supposedly cognizant of the deeply troubling social ontology of American prejudice, would know better than to resort to such pandering of the populace. One would think that, and one would be wrong.
Now, I don't think that that Hillary Clinton represents a truly "leftist" option in American politics.... but I do think that her struggle as a woman ought to remind us that we've still got a long way to go, baby. I don't think she should drop out of the race because I think we need to keep having this conversation. Maybe, hopefully, when the Democratic nomination is said and done, Obama will look back and see that it is his charge to comment on what his success both represents and defies about American "progress"-- that is, even in our most racially-progressive moments, we still aren't attuned to the women on whose backs this country continues to be built.