Nate Silver says, if things stay the same, predicting what will happen on election day will be a crapshoot at best.
If the current polls hold, predicting the election outcome will boil down to making a series of educated guesses about the relationship between state and national polls, and between the Electoral College and the popular vote.
There have been plenty of elections before when the outcome was highly uncertain down the stretch run or on Election Day itself. But I am not sure that there has been one where different types of polls pointed in opposite directions. Anyone in my business who is not a bit terrified by this set of facts is either lying to himself — or he doesn't know what he's doing.