The polls have all shown an upswing in the fortunes of John McCain since he picked Sarah Palin as his running mate.

Perhaps more importantly so has Intrade. Intrade is not a poll, it’s a free market wherein people place bets on the outcome of future events by buying or selling “contracts.” The more likely the market thinks–at the moment–that the event is to happen, the higher the price of a contract. While political polls endeavor to assemble a representative sample of people and ask them how they intend to vote, hoping that will predict how the actual turn-out on election day will vote, with Intrade, people independently decide to put their money where their mouths are.

Sometimes it is very hard to assemble a representative sample and it is still somewhat an art form. Sometimes people just don’t tell pollsters how they intend to vote (or how they did vote: early exit polls were wildly wrong in 2004). But no one is going to lie when they bet on Intrade. And having to put up real money, like the prospect of being hanged, concentrates minds wonderfully. The result is remarkable accuracy. In 2004, Intrade correctly predicted the outcome of the presidential election in every single state, even those the pollsters thought too close to call.

So it is interesting that while Obama has been consistently in the 59-61 range (peaking in mid-July, just before his foreign trip, at about 67) ever since the primary season ended in June, he has suddenly fallen to 48.1 as of this morning. In other words, while 60 percent of the traders thought Obama would win two weeks ago, now only 48 percent do.

You can follow the daily action at RealClearPolitics , right beneath the poll average on the right, and follow the action as it changes day by day in every state by state here. The latest state-by-state data (from September 9th) shows the electoral college race at 260 for Obama, 247 for McCain, 31 dead heat (270 needed to win). But just since the previous day, Ohio went from dead heat to weak McCain and Virginia and Colorado went from weak Obama to dead heat.

Warning: political junkies may find Intrade is their new drug of choice.