On February 15, 1898, a massive explosion shattered the American battleship Maine in Havana Harbor, killing 260 men. Although the exact cause is unknown, the sinking was widely attributed to deliberate sabotage by Spain. By April 1898, public pressure was such that despite all his efforts to hold back the tide of pro-war sentiment in the United States, President McKinley asked Congress for a declaration of war. Stirred by the slogan, "Remember the Maine," the Spanish fleet in the Philippines was sunk in retaliation for the American deaths. Although the Spanish-American War, known as the "splendid little war" for the United States, was short in duration it resulted in territorial gain, the occupation of the Philippines, and a bloody insurrection by the Filipinos that lasted more than three years and cost thousands of lives.

Americans had traditionally resisted becoming involved in the affairs of other nations...