The United States became an imperialist nation at the end of the 19th century because Americans wanted to expand over seas with their belief in manifest destiny. The three factors that started American imperialism were political and military competition including the creation of a strong naval force, economic competition among industrial nations and a belief in the racial and cultural superiority of people of Anglo-Saxon decent. The Spanish American War marked the emergence of the United States as a world power. This brief war lasted less than four months from April 25 to August 12, 1898. A number of factors contributed to the United States decision to go to war against Spain. These included the Cuban struggle for independence, American imperialism and the sinking of the United States warship "Maine". As a result of the war Spain ceded Guam, Puerto Rico, and the Philippines to the United States. The United States in turn, paid Spain $20,000,000 for public property in the Philippine Islands. The United States gained colonies on both sides of the Pacific including Hawaii. On August 12, 1898 Congress took control and proclaimed Hawaii American territory, and issued the open door policy, which were messages that president John Hay sent to Germany, France, Russia, Britain, Italy and Japan asking the countries not to interfere with the United States trading rights in China. The United States had long been interested in a Central American canal to link its east and west coasts, expand trade and for military interest. In 1902 President Theodore Roosevelt decided on Panama over Nicaragua and negotiated a treaty with Columbia giving the United States permission for the canal project. The Panamanians had authorized Philippe Bunau-Varilla an official of the French Canal Company to negotiate the terms and sign the agreement. The treaty also gave the United States the right to control the Canal Zone as if it were United States territory, and to annex more land if necessary for the Canal.