Ah, I assumed each senator was placed according to some measure of extremism, though in hindsight that alone should have produced crossings.
To support this interpretation, I noticed that the groups are not aligned - see for example George Allen's swerve in the 108th Congress. I suppose I was expecting it too, from having seen some visualization that tried and failed to find a tea party cluster.
To support this interpretation, I noticed that the groups are not aligned - see for example George Allen's swerve in the 108th Congress. I suppose I was expecting it too, from having seen some visualization that tried and failed to find a tea party cluster.