These events in Cuba coincided in the 1890s with a battle for readership between the American newspaper chains of Hearst and Pulitzer. Hearst's style of "yellow journalism" would outdo Pulitzer's, and he infamously used the power of his press to influence American opinion in favor of war. Often completely fabricated or just simply inflammatory, Hearst published sensationalized tales of atrocities which the "cruel Spanish" (see Black Legend) were inflicting on the "hapless Cubans". Outraged by the "inhumanity" of the Spanish, Americans were stirred up to pushing for an "intervention", which even the most jaded hawks, like a young Theodore Roosevelt, would treat as a mostly dress-up affair. Hearst is famously quoted in his response to a request by his illustrator Frederic Remington to return home from a uneventful and docile stay in Havana, writing: "Please remain. You furnish the pictures and I'll furnish the war."
There were, however, more genuine pressures pushing towards war. The United States Navy had recently grown considerably, but it was still untested, and many old war dogs were eager to test and use their new tools. The Navy had drawn up plans for attacking the Spanish in the Philippines over a year before hostilities broke out. The end of western expansion and of large-scale conflict with Native Americans also left the Army with little to do, and army leadership hoped that some new task would come. From an early date, many in the United States had felt that Cuba was "rightly" theirs. The so-called theory of manifest destiny made the island just off the coast of Florida seem an attractive candidate for American "expansion". Much of the island's economy was already in American hands, and most of its trade, much of which was black market, was with the U.S. Some business leaders pushed for conflict as well. In the words of Senator John M. Thurston of Nebraska: "War with Spain would increase the business and earnings of every American railroad, it would increase the output of every American factory, it would stimulate every branch of industry and domestic commerce."
http://en.wikipedia.org/wiki/Spanish-American_WarWhen the US accepted the Marielitos, it was stating that its "own" citizens have a home on the mainland.
When the US sent Elian back to Cuba, they admitted to Cuban sovereignty and pretty much acknowledged Cuba's right to exist as a free and separate nation.
Thanks be to Scarface.