Obama is not a true pacifist. He is not a real humanitarianist. If you are a peace organization and tend to endorse or campaign for Obama, I think one question is worth considering: will Obama change the situation of Military Industry Complex in US, which make huge profits from robbing American people and killing many people around the world and is the biggest factor of global instability and the biggest threat to world peace? Or more likely Obama will sleep in bed with those Military Industry Complex, and continue the killing of innocent people around the world and add more young people to the killing machine created by the Military Industry Complex.
As Gravel said, the worst thing you can do is to raise the expectation high and cannot deliver it. People will be more disappointed when he failed his promise. In this sense, Obama is the worst of the Democratic candidates.