Peggy Noonan has some good insight presented with her usual understated elegance.

Here I think is a central problem. I don't think voters see Mr. Obama as "the Democrat." I think they see him as Obama—unusual, singular. He's not your basic Dem, he's his own phenomenon, his own distinctive and, in a way, partyless self. "I am one of you," said the last two Democratic presidents, Jimmy Carter and Bill Clinton. But Mr. Obama doesn't carry that vibration, or fit into the old categories. Is he a lunch-pail Dem? No. Old-time big-city ethnic Dem? Southern Dem? Nah. He's new, young, and still exotic. He's cerebral, urbane, detached. I suspect he picked Joe Biden in part because Mr. Biden is part of the Democratic brand in a way Mr. Obama isn't.

What should he do? The answer to that is connected to another question. It is: Isn't it odd, and discomfiting, that we know so little about how each candidate thinks? What his philosophy is? We know their specific stands, but as to how they think, Mr. McCain often seems to be making it up as he goes along, and Mr. Obama often seems to be concealing it.

Here's a way to reveal more. Mr. Obama should give a series of speeches on "Why I am a Democrat." What does he think it means to be a Democrat? What is the Democratic Party, what is its role and purpose in America's political life? What does it exist to do? Why does it matter?

For Mr. Obama this might have the virtue of associating himself with an old brand, as they say, which might make him look less alone up there. It might help him speak to and persuade older working-class and middle-class Democrats, especially women. But more important, it might make how and what he thinks clearer to everyone, to all voters.

I think this would be a tremendously effective thing to do.  Not only would it perhaps allow him to break through to the traditional democrats who are hesitant to vote for somebody as different as Obama, but it might also give an affirmative reason to those who are voting for him simply because they can't bear the thought of McCain.  What do others think?