I am reading a paper from 2004 called, "Spatial Model of US Senate elections" which I have posted on the right bar. It comes to some startling conclusions about the effects of our staggered primary process in terms of Senate electios.
Basically, the author finds that the equillibrium is such that:
"The stable long-run result of full divergence." In other words, for any given state, senator one will expect to have fully opposite views to senator two, in the long-run. I don't though - it seems that if anything, senators from a given state are holding more similar views than ever. But I could be wrong about that.