Shorter Sean Trende [really] of RealClearPolitics: "It is just this bizarre, perfect storm of events that got us to this place."
So if you're a strategic voter, the thing to do is to check the RealClearPolitics poll average for your state on the morning of the election, and vote for whichever candidate is leading there? (Note to readers: That shameless plug for Sean's fine site was not in any way solicited. I myself check it like one of those rats in lab experiments, pressing the little lever to get another pellet.)
I knew it.