History of the Panama Canal
During World War II, the canal proved a vital part of the U.S. military strategy, allowing ships to transfer easily between the Atlantic and Pacific. Politically, the Canal remained a territory of the United States until 1977, when the Torrijos–Carter Treaties began the process of transferring territorial control of the Panama Canal Zone to Panama, a process completed on 31 December 1999.
Panama Canal Zone
In 2008, during a minor controversy over whether Canal Zone–born John McCain, born in the Zone in 1936, was legally eligible for the presidency, the US Senate passed a non-binding resolution that McCain was a "natural born Citizen" of the United States.