In my last Washington Examiner column, I looked at the possibility of two impossible things — impossible things in the sense used by Alice and the Red Queen — happening in the already turbulent 2016 presidential cycle. Here I’ll look at another, the possibility that the partisan dividing lines that have endured with little change for two decades might suddenly shift and change.

This has happened before. History teaches two lessons pointing in opposite directions: Partisan divisions can stay the same for a long time. And they can change suddenly and without much warning.