In the last decades of the nineteenth century, many Americans reassessed and abandoned their traditional isolationist policy. Due to growing industrial power, trade and contacts with Latin America increased. In the Pacific, American interest in Hawaii led to its annexation in 1898.
In 1898, the United States went to war with Spain. Americans generally sympathized with an independence movement in Cuba that sought to overthrow Spanish rule. The Spanish-American War was over in six months. As a result of the war, the United States gained a colonial empire and with it the challenge of governing overseas territories—Puerto Rico, Guam, and the Philippines. Questions soon arose over whether native people living in colonial possessions were entitled to the same civil rights as American citizens. Eventually, the Supreme Court of the United States ruled that the Constitution did not protect overseas possessions.
As the United States expanded into the Pacific, Americans became anxious to renew trade opportunities with the Chinese. To protect any potential trade between the two countries, Secretary of State John Hay asked the Chinese in 1899 to grant an "Open Door" trade policy.
President Theodore Roosevelt further strengthened American involvement in world affairs. He defended Venezuela from possible European aggression, and he issued the Roosevelt Corollary, a statement that attempted to justify United States intervention in Latin America. In addition, Roosevelt negotiated an end to the Russo-Japanese War. Perhaps most importantly, Roosevelt prevented Colombia from putting down an insurrection in Panama City. This action allowed Panamanians to establish the Republic of Panama. Roosevelt quickly negotiated a treaty with Panama for the right to build a canal across that nation.
