I think Andrew Sullivan is on to something here:
One difference between Obama and Clinton does not seem to me to have been stressed enough. They are of different Democratic generations. Clinton is from the traumatized generation; Obama isn't. Clinton has internalized to her bones the 1990s sense that conservatism is ascendant, that what she really believes is unpopular, that the Republicans have structural, latent power of having a majority of Americans on their side. Hence the fact that she reeks of fear, of calculation, of focus groups, of triangulation. She might once have had ideals keenly felt; she might once have actually relished fighting for them and arguing in thier defense. But she has not been like that for a very long time. She has political post-traumatic stress disorder. She saw her view of feminism gutted in the 1992 campaign; she saw her healthcare plan destroyed by what she saw as a VRWC; she remains among the most risk-averse of Democrats on foreign policy and in the culture wars.
Obama is different. He wasn't mugged by the 1980s and 1990s as Clinton was. He doesn't carry within him the liberal self-hatred and self-doubt that Clinton does. The traumatized Democrats fear the majority of Americans are bigoted, know-nothing, racist rubes from whom they need to conceal their true feelings and views. The non-traumatized Democrats are able to say what they think, make their case to potential supporters and act, well, like Republicans acted in the 1980s and 1990s. The choice between Clinton and Obama is the choice between a defensive crouch and a confident engagement. It is the choice between someone who lost their beliefs in a welter of fear; and someone who has faith that his worldview can persuade a majority.
The recent dust up between Obama and HRC over diplomacy is a case in point. And it applies not just to HRC, but to any GOP candidate Obama would face.
One of the Republicans playing cards for the last several decades has been their perceived "toughness" in foreign policy. But this apparent toughness is in many cases just a cloak for fear.
Consider the fear phrase HRC uttered in response to Obama during the debate: I don't want to be used as a propaganda tool. That's a statement rooted in fear. It's not a statement of confidence, particularly the statement of confidence that should emenate from the leader of the most powerful nation in the world. It demonstrates fear, a skittishness about political engagements of all kinds. It's severely risk-avoidant, perhaps neurotically so.