United States territorial acquisitions
The Panama Canal Zone was an unorganized US territory located within the Republic of Panama. It was established under the Hay–Bunau-Varilla Treaty in 1903 and disestablished in 1979 under the Torrijos–Carter Treaties. Panama gained full control over the Panama Canal in 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.