Betting on the future

I hear that at an Internet site, the betting is over 60% for Barrack Obama to win the Presidency of USA, with John Mc Cain trailing at 36%. Statisticians give a lot of credibility to such betting by the public, as it accurately assesses the probability of events. Years ago, there was a proposal by the Defense Dept. to encourage betting on the probability of terrorist attacks in USA, for getting early warnings! It was dropped because almost everyone found it so outrageous.