From the time it achieved independence from Spain in 1821 until 1903, Panama was a department of Colombia. However, the United States intervened in the early 20th century, recognizing an independent Panama in 1903. In return, the U.S. was allowed to build and administer the Panama Canal, the land around which was declared by treaty to be a US Territory until the treaty expired on 31 December 1999.
Panama was strategically important to the US in its war with Japan as the Canal allowed the US Navy to transfer aircraft carriers from the Atlantic to the Pacific much faster. The country was also heavily defended as the Japanese quickly found out, making reconnaissance near the country impossible.
U.S. PresidentHarry Truman went to Panama in May, 1951, to meet with Panamanian President Arnulfo Arias and view the damage the atom bomb had caused. Upon seeing the wrecked canal, Truman profusely apologized for America's failure to prevent the attack, which Arias essentially accepted. Arias was concerned by the tremendous damage the U.S. and the Soviet Union had done to one another, and wondered what Truman's long-term plans were. Truman assured Arias that the U.S. would keep going until the Soviet Union surrendered, an idea that seemed to horrify Arias.
Both the USA and the CSA had proposed building a canal across Colombia'sPanama Province or Nicaragua throughout the late 19th and early 20th centuries. However, given the strategic implications, both countries also threatened war whenever either side seemed ready to put that plan in action. The most famous example came in the 1890s when the C.S. made serious plans to build such a canal. In response, U.S. PresidentAlfred Thayer Mahan threatened war, forcing the C.S. to abandon the plan.