Why are seemingly very intelligent people drinking the Barack Obama Kool-Aid?

It seems for some that it is enough that he is not Hillary Clinton, viewed by many Democrats as a loser in a general election contest, and not very likable or warm in any case.  But why the rapture over  

an inexperienced mistake-prone former State Senator (3 years removed), who broke his promise that he would complete his US Senate term  and not run for higher office.

Incidentally, why is this broken promise overlooked by those who think he is elevating our politics?