a cadre of returned missionaries who were helpful, and ethnic groups, especially the Irish and the Germans and the Jews had their own national experts whose views appeared in their own periodicals. Cuba and Spain In the mid 1890s, American public opinion denounced the Spanish repression of the Cuban independence movement as brutal and unacceptable. The U.S. increased pressure and was dissatisfied with Spanish responses. When the American battleship the exploded for undetermined reasons in the harbor of Havana, Cuba, on 15 February 1898, the issue became overwhelming and McKinley could not resist the demands for immediate action. Most Democrats and many Republicans demanded war to liberate Cuba. Almost simultaneously the two countries declared war. (Every other country was neutral.) The U.S. easily won the one-sided four-month-long Spanish–American War from April through July. In the Treaty of Paris, the U.S. took over the last remnants of the Spanish Empire, notably Cuba, Puerto Rico, the Philippines and Guam. It marked America's transition from a regional to a global power. Cuba was given independence under American supervision. However the permanent status of the Philippines became a heated political issue. Democrats, led by William Jennings Bryan, had strongly supported the war but now they strongly opposed annexation. McKinley was reelected and annexation was decided. The U.S. Navy emerged as a major naval power thanks to modernization programs begun in the 1880s and adopted the sea power theories of Captain Alfred Thayer Mahan. The Army remained small but was reorganized in the Roosevelt Administration along modern lines and no longer focused on scattered forts in the West. The Philippine–American War was a short operation to suppress insurgents and ensure U.S. control of the islands; by 1907, however, interest in the Philippines as an entry to Asia faded in favor of the Panama Canal, and American foreign policy centered on the Caribbean. The 1904 Roosevelt Corollary to the Monroe Doctrine, which proclaimed a right for the United States to intervene to stabilize weak states in the Americas, further weakened European influence in Latin America and further established U.S. regional hegemony. The outbreak of the Mexican Revolution in 1910 ended a half century of peaceful borders and brought escalating tensions, as revolutionaries threatened American business interests and hundreds of thousands of refugees fled north. President Woodrow Wilson tried using military intervention to stabilize Mexico but that failed. After Mexico in 1917 rejected Germany's invitation in the