Jay Cost, the brilliant young political scientist tells us why campaign polls at this point are little more than media echo chambers and not of value:

Polls are valuable to a point - but they really cannot be taken as independent evidence of the state of the race. This is how the media's echo chamber is created. The media talks up one candidate over another. The polls echo this talking up back to the media. The media believes the polls offer independent evidence that justifies its talking up, and proceeds to talk up the particular candidate all the more.

This is why I refuse to ask the question that Dan Balz asked this week. The manner in which voters make a selection will change - because of all the money that candidates have. That's when the real campaign begins, you know. It begins when the candidates start their advertising blitzes. That has only begun - and so the campaign has only begun. The fact that the media has nothing better to talk about in August than the "campaign" does not mean that there is a campaign to talk about.

The campaign - the real one - could change everything. Barack Obama will have something on the order of $60 million to communicate to primary voters. Clinton, of course, will be equally well-funded. But the point is that, as far as the average voter is concerned, the media dialogue is about to be drowned out by the the actual campaign. Right now, the media and political elites are the ones largely influencing polling numbers. Starting next month, the candidates are going to be the ones influencing those numbers. And so, average voters are going to have an opportunity to hear Clinton and Obama. Both of them will have an opportunity to say their piece, and have their piece heard, prior to Election Day. Accordingly, the way in which the average person's vote choice is informed is quite different than the way in which the average person's selection in a July poll is informed.

And so, we are left with the following question about the Democratic primary. It is, not coincidentally, the one that we began asking back when Obama declared. Clinton offers experience and steady stewardship. Obama offers change. Which will Democratic voters prefer? Despite all of the chatter from the pundit classes - the fact remains that we do not yet have an answer to this question.