Paul W. answered 04/11/19
Dedicated to Achieving Student Success in History, Government, Culture
By the 1890s, the United States of America encompassed all of the territory that the continental United States contains today; it stretched from the Atlantic to the Pacific Ocean. It contained the largest population of any nation in the Americas and a world class industrial economy. As such, it's hardly surprising that the United States wielded a great deal of influence within the Western hemisphere. This included the involvement of both private U.S. citizens and U.S.businesses in the countries of Latin America. Business opportunities attracted investors. In Cuba, U.S. individuals and companies invested in profitable businesses, sugar and tobacco plantations in particular (the main cash crops grown in Cuba).
Unfortunately, Cuba was a deeply troubled island. By the 1820s all of peoples of Latin America had freed themselves from Spanish and Portuguese rule. That is, all but a few islands in the Caribbean, the largest and most important of which was Cuba. Cuba remained a colony of Spain, but the majority of the people living in Cuba wanted to follow the example of their cousins in the rest of Latin America. More than once during the 19th century the Spanish Colonial government in Cuba was faced with armed rebellion. The latest uprising by Cuban patriots had begun in 1895.
Sugar and tobacco plantations, along with other investments in Cuba partially or fully owned by U.S. citizens and U.S. companies were endangered by the fighting between Cuban patriots and Spanish troops. The weakness of the patriot forces led them to rely on guerrilla warfare, which was met by a ruthless counterinsurgency campaign by the Spanish. Both sides targeted private property, including property owned by U.S. investors.
This alone would have provoked the involvement of the United States government in the conflict. But concern for the safety of U.S. owned private property was compounded by an aroused U.S. public, which was inflamed to a large degree by 'Yellow Journalism'. Powerful U.S. newspapers that had widespread circulation sought to exploit the fighting in Cuba to increase sales. Sensational stories were published detailing Spanish atrocities, both real and imaginary, almost always in a manner designed to excite anger in readers. Public anger against the Spanish and sympathy for the Cuban patriots created pressure on the U.S. government to take action.
President McKinley chose to dispatch a warship, the U.S.S. Maine, to Havana harbor. This was a classic example of 'Gunboat Diplomacy'. During the 19th century, when the overseas interests of a powerful nation, such as Great Britain, were threatened, the nation in question would send one or more warships to the country where its interests were in danger. The presence of these warships in a country's main port served as a veiled (and not so veiled) threat, designed to intimidate the government of the country in question. The presence of the U.S.S. Maine was intended to put pressure on the Government of Spain to find a means of resolving the conflict with the Cuban patriots.
The likelihood of a peaceful was very slim. The goal of the Cuban patriots was complete independence, they were unlikely to end their rebellion until the Spanish had left Cuba. For the Spanish, Cuba was far too profitable to voluntarily surrender to what they viewed as a rag-tag collection of bandits. Even entering into negotiations with the Cuban rebels was out of the question in the eyes of the Spanish government.
Of course, before either party of the conflict could see their way to changing their minds, circumstances were radically transformed by the explosion of the U.S.S. Maine. Today, the accepted explanation is that coal dust in the ship's coal bunkers were accidentally ignited, causing a catastrophic explosion. But at the time, the same U.S. newspapers that had inflamed U.S. public opinion reported - without evidence to support their claim - that the Spanish had intentionally detonated an underwater mine in order to destroy the U.S.S. Maine. "Remember the Maine and to Hell with Spain!" became the cry among the U.S. public, and a declaration of war with Spain soon followed...
Note: The question that the U.S. public neglected to ask at the time was 'What would the Spanish have to gain from blowing up a U.S. warship?' The consequences of such an unprovoked act of aggression by the Spanish government was easily predictable - war with the United States. The detonation of an explosive device under the U.S.S. Maine would, therefore, have made no sense for the Spanish, who had their hands full trying to suppress the rebellion in Cuba.