Welcome to the liberal backlash?

Kevin Drum over at Politcal Animal nails something that I've been thinking about for a while.

The only question I have is how much of this is dependent on personalities (LBJ's, W's) and how much is due to those political realignments we hear about happening periodically during American history. Think about who the Democrats and Republicans are right now, and who they were in say, 1868. If we're due for or in a realignment like the last one--Reagan's--they sure do move at a geological pace.