One could look at the state-by-state markets in the weeks leading up and see if the probability predicted differed greatly from the main market. It would be far

One could look at the state-by-state markets in the weeks leading up and see if the probability predicted differed greatly from the main market. It would be far trickier to manipulate the markets state by state in such a way that their probable outcomes aligned with the probable outcome of the national markets. I just looked at the InTrade state numbers from 11/2 (which I have on a spreadsheet) and running a few dozen simulations I was getting Obama winning about 80%. That's a pretty significant difference from where the national numbers were on 11/2 (I think about 66% maybe?) Of course, if they differ it might just be because the Intrade market is imperfect, in which case it would represent a nice arbitrage strategy for the next election...