There were two accounts, one in a news article, the second in the editorial section, telling the minihistory of Pol Pot, sometime plenipotentiary ruler of Cambodia.
-- William F. Buckley Jr., The Redhunter
At that time, Egypt was our protectorate, which meant the High Commissioner was the plenipotentiary of George V and carried independent authority.
-- David Freeman, One of Us
Lastly, in Sparta we meet the Ephori, and in Rome with the Tribunes; two bodies, small indeed in number, but annually elected by the whole body of the people, and considered as the representatives of the people, almost in their plenipotentiary capacity.
-- Alexander Hamilton, James Madison, John Jay, and Clinton Rossiter, The Federalist Papers
Plenipotentiary derives from Latin plenus, "full" + potens, "powerful."