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 reason why the Framers of the Constitution wanted the selection of justices to be non-democratic is because they didn't wanted these justices to be "swayed" by public opinion, which could allow them to make judicial decisions based on what would most likely get them re-elected, as opposed to what was in the best interest of the country.