He wouldn't be Obama. It is that simple. If he was white, female, differently abled, whatever, he would not be Obama. The man is where he is because of who he is and he is who he is because of the experiences that have shaped him. A central part of that experience comes from growing up as a man of color in the United States. His experience shaped his career choices. It presented him with a specific mix of opportunities, culture, and obstacles - all of which contribute to the man he is today. It shaped his message. It shaped his view of America. It shaped his dreams of what he could be and what we could be. So yes, Geraldine Ferraro, were Obama not black, he would not be where he is. But that is no different than saying, "if an eagle didn't have wings, it couldn't fly."
Of course, that is not what Ferraro meant. She meant that he is not qualified and that somehow, Barack Obama is the recipient of some kind of affirmative action for politicians that catapults him to the front of the line because of race. He is not capable but we'll give him a shot because he's black. She is belittling him... and all of the rest of us. It gives those who are blatantly racist a good excuse to not even consider Obama and it calls into question the judgment of anyone who is in the Obama camp.
This represents racism of the worst kind. It plays on all of the old stereotypes of a black man both as incapable and as irresistible. Just as race seems to be receeding as an issue in American life, it calls it back to the forefront and renders any progress we have made as suspect. That Ferraro doesn't seem to get it only shows the depth of racism in her. That Hillary Clinton has not condemned the statement in a categorical way only shows the degree to which she is willing to turn her back on what is right if it is politically expedient.
Of course, Obama is not only black. He is male. He is well educated. He comes from the midwest in urban settings. He had a specific experience of class. He has a lifetime of experience in the African American Church. He has a genetic makeup with certain abilities hard-wired into him. He has a wide variety of descriptors, each of which has served to help shape him into the man he is. And there is something in his character that has decided how each of these influences would change him. All in all, of the choices available, it adds up to the candidate for whom I would like to vote for president.