Colombia's senate had just rejected a treaty that would have let the United States build a canal across the isthmus. Local leaders, backed by the French engineer Philippe Bunau-Varilla, declared independence, and the USS Nashville kept Colombian troops from reaching Panama City.
The United States recognized the new republic within days. Two weeks later a treaty gave it control of a canal zone, and the Panama Canal opened in 1914. Manuel Amador Guerrero, one of the leaders of the movement, became the first president.
Source: Wikipedia