Flip-flopping has a long, if not honored, history. The blog Boston 1775 moves south to Philadelphia to take note of a Revolutionary era flip-flopper in three posts. New Year's Day 1777, New Year's Day 1778 and the justification from later in 1778, after the Brits had left Philadelphia.
The last shows that the Reverend Witherspoon had a wicked sense of humor, and provides a justification which our modern day politicians could use as a pattern: "I was neither pro-[insert word of your choice, war, individual mandate, conservative, whatever] nor anti-[insert the opposite word], I was a politician.
Incidentally, I note that the verse from 1777 calls upon God, while the verse from 1778 calls upon the classical gods of Greece and Rome. Probably not significant.