>>The whole thing seems to shift left or right over time.<<
Although that may be true in the VERY long run, there is no evidence of any shift to the right that I am aware of since the signing of the declaration of independence. There has been plenty of shift to the left, however.
I may have missed something, but what would you say shifted to the right of our founding fathers in the last 240 years?
I would say pretty much all the amendments were shifts to the right.