Thousand Days' War
On November 3, 1903 Panama separated from Colombia with the direct support of the United States. On November 6, the United States recognized Panama's sovereignty and on November 11, the United States informed Colombia they would oppose Colombian troops if they attempted to recover Panama and backed the claim by sending warships to the isthmus. The Thousand Days' War, along with political disorganization in Bogotá, had left Colombia too weak to oppose the separation. On November 18, the United States signed the Hay–Bunau-Varilla Treaty with Panama for the construction of the Panama Canal.