By Patrick Appel
Matt makes a good point:

Basically, predictions range from Obama winning narrowly to Obama winning easily with one guy calling it a toss-up. In other words nobody thinks McCain is likely to win. My take on this is that the election is more unpredictable than the "Obama in a landslide" crowd thinks primarily because the fundamentals themselves are unpredictable. I don't think it's likely that there'll be a marked turnaround in economic conditions over the next few months, but macroeconomic trends are famously hard to forecast. Similarly, none of us really know what's going to happen in Iraq over the next few months. Elections are primarily determined by the fundamentals, and thus are in that sense more predictable than journalists usually imply, but it's not as if the fundamentals are all that easy to predict.