Liberal iconoclast has not written book smearing McCain, gone on the air to promote the lies, and been sponsored by a millionaire to spread his belief that McCain is senile.

He has said it in the context of a left-wing blog. It's really his opinion, rather than a smear, because he's not trying to spread it out in the general public to discredit McCain.
I'll bet all kinds of nasty things about Obama are said on right-wing blogs, and most of them will be lies actually started by the right-wing propaganda machine, like Obama is a Muslim, like he's not a citizen, like his birth certificate is fake. These lies are not opinions of bloggers, they are deliberate lies started by a media campaign to smear Obama.

"Every gun that is made, every warship launched, every rocket fired signifies in the final sense, a theft from those who hunger and are not fed, those who are cold and are not clothed." Dwight Eisenhower