The protocol was negotiated by William Day, the U.S. secretary of state, and Jules Cambon, the French ambassador who represented the Spanish authorities in Madrid.
It required Spain to “relinquish all claim of sovereignty over and title of Cuba” and to cede Puerto Rico and the Pacific island of Guam to the United States.
Furthermore, according to the protocol, “the United States will occupy and hold the city, bay and harbor of Manila, pending the conclusion of a treaty of peace which shall determine the control, disposition and government of the Philippines.” It took until July 4, 1946, for Washington to relinquish sovereignty over the Philippines.
Cubans formed their own civil government and attained independence on May 20, 1902. But with the departure of U.S. troops, Washington barred Cuba from entering into alliances with other nations and secured a perpetual lease on its naval base at Guantanamo Bay.
The Spanish-American War lasted four months. John Hay, the American ambassador in London and a future secretary of state, wrote his friend Theodore Roosevelt that the conflict had been “a splendid little war.” Many newspaper accounts stressed how Northerners and Southerners, blacks and whites, had fought together against a common foe, an approach that helped heal the scars from the Civil War.
The brief struggle marked the effective end of the Spanish empire — Spain’s overseas holdings were trimmed to a few African colonies. The conflict also marked, along with the annexation of the Hawaiian Islands, the full-blown entry of the U.S. into world affairs.
Source: “The War with Spain in 1898,” by David Trask (1996)