Did the US use the political or the human rights method with regard to the Panama Canal?
I assume that you are talking about the US returning the Panama Canal to Panama, not the circumstances that surrounded the creation of Panama and the building of the canal.
If so, I would argue that the US used a human rights approach. Under President Carter, the US approach was to see foreign policy more in terms of the rights of the people of other countries. The thinking with regard to the Panama Canal was that the US had no right to own a strip of land through another sovereign country. Thus, the US paid attention to the human rights of Panamanians and the sovereignty of their country and gave back the Panama Canal.