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.
World War II by country
The small Panama Canal Zone was United States territory, and American forces from the U.S. Navy, U.S. Army, the USAAF (at Howard Air Force Base), and Colombian forces helped inside the Canal Zone, guarded the Panama Canal from both ends. This Canal provided the United States and its Allies with the ability to move warships and troops rapidly between the Atlantic Ocean and the Pacific Ocean. Since most of the American shipbuilding capability was on the East Coast and the Gulf of Mexico, the Canal was vital for moving new warships to the Pacific to fight the Imperial Japanese Navy