The premier immediate cause, of course, was the sinking of the U.S. battleship Maine in Havana harbor on Feb. 15, 1898, with a loss of 260 men. Prior to that was a long and protracted war fought by Cuban patriots against Spain with the goal of achieving independence. A number of intervening events occurred, but all had the result of solidifying America's support for expelling the last vestiges of European colonization fromt he western hemisphere...
I do not disagree with the above answer but would suggest that fighters attempting to overthrow an established government, such as the Americans in their war of independence, are rebels, and not patriots. Patriots are the people on the side of the existing government.