Lengthy, but excellent and well-worth reading article from The New York Review of Books on the Clinton/Obama fight

...written by author and reporter Elizabeth Drew.

Too many good paragraphs to quote, but here's an early one to give you a taste:

In this fight, the Clinton camp is the more aggressive of the two, and it's adept at what might be called molehill politics: making a very big deal in the press about something that's a very small deal—such as a single word in a mailing or a slip-up by an aide. Clinton's strategists pounce on whatever opportunity presents itself to attack Obama, and try to knock him off his own message, and his stride. Clinton's approach resembles her tactics in the White House, in which her inclination was to attack (which caused a number of problems, and was one of the reasons her health care bill was defeated). The Obama camp has sometimes been slow, and even reluctant, to respond, because if he attacks her personally (which the Clinton campaign would like him to do), he's not Barack Obama anymore. Moreover, Obama takes care not to come across as the "angry black"—a stereotype he does not fit, but that could be imposed upon him by others.