[j_h_s]

Every two years, a third of the senate is elected for a six year term. So no senate election can express the will of the entire nation.

[wildmusings]

I see your point, but you've got it a bit backwards. The reason for spacing out the Senate elections is to temper the political winds. Had the whole Senate been up for grabs in 2014, it would have been an even bigger Republican sweep.