Over the past few days, the Obama campaign has been claiming — both in ads and in statements by Barack Obama himself — that John McCain would “cut” Medicare benefits by “$882 billion,” a charge that the Associated Press called “shaky” and that FactCheck.org bluntly dismissed as “bogus” and “false.”

Yet of the three broadcast networks, only ABC News has thus far joined the condemnation of Obama’s deceptive ad. NBC on Monday would only go so far as to say “McCain’s advisors say that’s not true...” — implying that it’s merely a partisan difference of opinion — while CBS has thus far refrained from questioning Obama’s truthfulness on this issue.

For weeks now, the networks have complained about the McCain campaign’s supposed nasty and unfair campaign attacks against Obama, so when will NBC and CBS join ABC in punishing this nasty and unfair charge from the Democrats?