The Spanish American War was in many respects an unnecessary war which the United States virtually provoked. An indirect cause of the war was the emerging interest of the United States in expanding its influence beyond its borders. True to its self professed adherence to the Monroe Doctrine, the U.S. looked to Cuba as a area of interest. A more direct cause was the hyperbole and overheated news stories published in the New York Herald, and the New York World, published by William Randolph Hearst and Joseph Pulitzer respectively. The two publishers were in cutthroat competition with each other, and truth took a second chair to newspaper sales. When a civil war broke out in Cuba, both were quick to publish detailed accounts of Spanish atrocities on the island. Hearst even sent famed photographer Frederick Remington to Cuba to capture pictures of Spanish mistreatment of the Cuban people. Legend has it that when Remington told Hearst there were no atrocities and in fact no war, Hearst replied, "you furnish the pictures, I'll furnish the war."
A convenient opportunity presented itself with the explosion and sinking of the USS Maine in Havana harbor. The explosion was entirely accidental, and there was every indication at the time that the explosion was an accident; but this was too good an opportunity for the two publishers to pass up. They published headlines screaming "Remember the Maine," and offering huge rewards for information leading to the arrest of the perpetrators. Spain, a weak empire at this point, attempted reconciliation with the U.S. on terms which were tantamount to surrender; however the U.S. government also saw this as too good an opportunity. President William McKinley, who had run on a campaign calling for an independent Cuba, ordered a blockade of Cuba on April 22, 1898. This was an act of war, and Spain declared war on April 24, practically out of necessity. Congress insisted on getting there first, and declared war on April 25, but backdated to declaration to April 21.
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When the battleship U.S.S. Maine exploded and sank in Havana harbor, this was the last push needed to force the country into this war. Of course the explosion and loss of life was blamed on Spanish forces, even though it was actually the result of a smoldering coal bunker fire (steamships still used coal then) that melted through a bulkhead into an ammunition locker. The United States forces were ready for a war and Spain's were not. It was a monumental mismatch and over quickly with the result that Cuba and The Philippines and several smaller islands became U.S. protectorates and Spain's time as a major world power was over.