Can’t blame him, although I don’t know how you solve this prisoner’s dilemma in an Internet age. One site floats the rumor, word spreads via e-mail, a few other sites blog it, another dozen sites reason that it’s gaining currency as a meme and already Google-able so there’s no reason to ignore it, and it’s off to the races. The media gets wind of it, checks it out, maybe runs a public advisory story debunking it (e.g., “No evidence of Michelle Obama tape”), and finally puts a question to the candidate himself to give him a chance to blow it out of the water. The story runs the next day, a million people read about it, ten percent assume that it’s at least partially true, and voila. How do you keep a conspiracy of silence when everyone in the world’s a publisher?

“We have seen this before. There is dirt and lies that are circulated in e-mails and they pump them out long enough until finally you, a mainstream reporter, asks me about it,” Obama said to the McClatchy reporter during a press conference aboard his campaign plane. “That gives legs to the story. If somebody has evidence that myself or Michelle or anybody has said something inappropriate, let them do it.”

Asked whether he knew it not to be true, Obama said he had answered the question.

“Frankly, my hope is people don’t play this game,” Obama said. “It is a destructive aspect of our politics. Simply because something appears in an e-mail, that should lend it no more credence than if you heard it on the corner. Presumably the job of the press is to not to go around and spread scurrilous rumors like this until there is actually anything, an iota, of substance or evidence that would substantiate it.”

There are some rumors so ludicrous that even the press, bless their hearts, won’t pester the man with a request for a formal denial, so why put this one to him? Does it meet some threshold of plausibility in their minds, or does the threshold have to do with how far it’s already spread? Because while it may be true that everyone’s a publisher, it’s also true, needless to say, that big media’s reach is still a lot longer than ours. This was my point about Mike Barnicle, fabricator and plagiarist, calling bloggers nitwits: I don’t mind being condescended to, but good lord, at least earn it.

Update: Oh, and lest the McClatchy reporter take the brunt of this, let’s remember which journalistic icon it was who really first shunted this into the mainstream. Right. Spitty.