Why Obama can't attack

Patrick Ruffini says the Democrats have learned the wrong lessons about offense and defense; instead of controlling the news cycle, Democrats find themselves responding to it.   That's bad in political campaigns for the same reason it's bad in sports.  If your offense doesn't get on the field, it doesn't matter how good your defense is.  You can't win.

Patrick suggests Democrats need to "[maintain] a 2-to-1 ratio of salable attacks to responses", and "changing the subject off Palin by launching some explosive new attack on McCain".   Generally speaking, that's correct.  If you don't like the current story, tell a better story. 

I'm not sure Barack Obama can win by attacking, though.  Consider why people like Obama in the first place.

• An ABC/Washington Post poll last week showed very similar results.  On the question of "personality and temperment to be President", voters supported Obama 57 to 35.
• In a CNN/Opinion Research Corporation Poll, Obama's best characteristics/qualities showing was in "can unite the country", where he won 53 to 37.
• According to an August Pew Poll, while voters overwhelmingly think John McCain wins on various "key leadership traits", Barack Obama's advantage is "being seen as the candidate who has new ideas and who connects well with ordinary people."

In particular, notice the "typical politician" numbers.  In a "change" election, "typical politician" is poison.  Keeping that number low is vital to Obama's campaign. 

If Obama goes negative, he tears down his carefully cultivated "new kind of politics" facade and reveals the typical politician behind it.  And if Obama is perceived as a typical politician, the central story of his campaign is decimated.  Voters, particularly independents, would be disillusioned and alienated.

Ruffini is right that the Obama campaign is struggling because they're so worried about playing good defense.  However, I'm not sure that Obama can pivot to offense without seriously damaging his own brand.

That would help explain why "Obama's campaign will no longer object to independent efforts that hammer John McCain".  If 527's are taking care of the attacks, Barack Obama can remain in character and his storyline holds.