Andy, this is not disagreement with your analysis so much as a tangent from it. I too think McCain has largely failed to make Obama look like the radical his background suggests he is or at least once was. (I mean M has failed both tonight and throughout the campaign.) I did, however, find M’s style rather combative tonight. He sounded liked the feisty old codger he is. But the substance of his attacks was relatively trivial: Obama isn’t tough enough on earmarks, he took Fannie/Freddie lobbying money, etc. So the negativity was squandered on blase criticisms that are true of half the Senate. Obama, meanwhile, sounds OH so earnest and comes across as the moderate, reasonable, suave post-partisan he wants to seem.
Of course if McCain hits Obama’s background too hard, he is persecuting a living saint. This difficulty of running against holy men.