Panama Canal
Colombia, France, and later the United States controlled the territory surrounding the canal during construction. The US continued to control the canal and surrounding Panama Canal Zone until the 1977 Torrijos–Carter Treaties provided for handover to Panama. After a period of joint American–Panamanian control, in 1999, the canal was taken over by the Panamanian government. It is now managed and operated by the government-owned Panama Canal Authority.
Dennis DeConcini
DeConcini sponsored an amendment (the DeConcini Reservation) to the Panama Canal Treaty of 1977 which allows the United States "to take such steps as each [the U.S. or Panama] deems necessary, in accordance with its constitutional processes, including the use of military force in the Republic of Panama, to reopen the Canal or restore the operations of the Canal, as the case may be."