Obama and McCain "exemplify 'post-partisan' politics."

Perhaps. And if so, it's clear — isn't it? — that Obama is the stronger opponent for the Republican's presumptive nominee. George Will lays out this theory well:

Forewarned, Democrats now are forearmed -- not that they will necessarily make sensible use of the gift.... Will their purblind party now nominate the most polarizing person in contemporary politics, knowing that Republicans will nominate the person who tries to compensate for his weakness among conservatives with his strength among independent voters who are crucial to winning the White House?

Will briefly alludes to something else, which is going to be important when the 2 party nominees appear side-by-side. McCain is quite old. He admits it and laughs about it, but it's a fact and it affects perceptions on a deep psychic level. Can a President be that old? Will voters have doubts? Hillary Clinton is old enough to neutralize the age issue or at least reduce our anxiety about it. Barack Obama will make us to think about it constantly.