The answer is:
They wanted to set up colonies.
On October 18, 1898, American troops fighting in the Spanish-American War raised the United States flag in Puerto Rico formalizing U.S. control of the former Spanish colony. General Nelson A. Miles had landed approximately 3,500 U.S. troops on the island on July 25. On August 12, Spain and the United States agreed to an armistice; on September 13, the Protocol of Peace was ratified; and on December 10, the Treaty of Paris was signed, ending the Spanish-American War.
The key to successful relationships lies solely in our ability to take the perspective of another. Perspective taking is that all important skill of being able to look at things from a point of view other than our own. Perspective taking brings in the mindfulness of compassion and empathy to our relationships.