Here are two excellent articles that point out the predicament in which Obama finds himself.
The first, by David Brooks, explains that campaigns cannot sell out their core message and proceeds to identify Obama's core weakness. Here's an excerpt:
In short, a candidate should never betray the core theory of his campaign, or head down a road that leads to that betrayal. Barack Obama doesn’t have an impressive record of experience or a unique policy profile. New politics is all he’s got. He loses that, and he loses everything. Every day that he looks conventional is a bad day for him.
Besides, the real softness of the campaign is not that Obama is a wimp. It’s that he has never explained how this new politics would actually produce bread-and-butter benefits to people in places like Youngstown and Altoona.
Next, Charles Krauthammer helps explain some of the psychological dynamics underlying Obama's rise. He then challenges the idea that Obama has the gumption to unite a riven polity. Here's an excerpt from this one:
The Obama campaign has sent journalists eight pages of examples of his reaching across the aisle in the Senate. I am not the only one to note, however, that these are small-bore items of almost no controversy -- more help for war veterans, reducing loose nukes in the former Soviet Union, fighting avian flu and the like. Bipartisan support for apple pie is hardly a profile in courage.
On the difficult compromises that required the political courage to challenge one's own political constituency, Obama flinched: the "Gang of 14" compromise on judicial appointments, the immigration compromise to which Obama tried to append union-backed killer amendments and, just last month, the compromise on warrantless eavesdropping that garnered 68 votes in the Senate. But not Obama's.
Who, in fact, supported all of these bipartisan deals, was a central player in two of them and brokered the even more notorious McCain-Feingold campaign finance reform? John McCain, of course.