conventional wisdom and pack mentality.
I like Obama, but he will have to prove that he can survive the excitation that comes with the fact that he is a new face. How often can you be on TV before you stop being a new face?
In addition, read the Sirota analysis concerning Evan Bayh.
http://www.workingforchange.com/blog/index.cfm?mode=entry&entry=536CFF3E-E0C3-F090-A39E19B1F023C672While Sirota is extremely harsh on Bayh (probably more than he deserves), part of what he says applies to Obama as well:
This is a typical career politician move - don't actually talk about what you are for, talk about what your party supposedly must talk about or not talk about. This kind of behavior usually comes from a person who actually has nothing important or substantive to say, other than "look at me, I want attention." And in this case, of course, Bayh doesn't even have the guts to define what "ideological" means. So let's do it for him: The American Heritage dictionary defines "ideological" as "Of or concerned with ideas."
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Obama sometimes has the same problem (and some other Democrats as well). He spends more time defining what Democrats should do and not do than saying what he stands for(I guess politicians that were formed by the Clinton school, whether they agree with Clinton vision or are more liberal, have this tendency -- trying to define how to win rather than your principles). This is the major issue I have with him.