The Platt Amendment was an amendment made in 1901 to a resolution of the United States Congress. It said that all treaties with Cuba had to be approved by the U.S. Senate and the U.S. had the right to interfere in Cuba's affairs if order broke down within Cuba. It also declared Guantánamo Bay to be U.S. territory. The Cuban–American Treaty of Relations of 1903 said the same things.
In the years following its enactment, until its abolition in 1934, the Platt Amendment was used on several occasions by the United States to intervene in Cuban internal affairs and protect US economic interests on the island.