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.
Presidency of Jimmy Carter
During its ratification debate, the Senate added amendments that granted the U.S. the right to intervene militarily to keep the canal open, which the Panamanians assented to after further negotiations. In March 1978, the Senate ratified both treaties by a margin of 68-to-32. The Canal Zone and all its facilities were turned over to Panama on 31 December 1999, and Reagan repeatedly attacked Carter on this issue in the 1980 presidential campaign.