The word Guantánamo refers in Europe to the US prison camp on its naval base and not to the city in eastern Cuba and not to the song Guantanamera (woman from Guantánamo). With the defeat in the Spanish-American War of 1898 Spain had to cede Cuba, Puerto Rico, its part of the Virgin Islands, the Philippines and Guam to the United States. But because there was already an independence movement among the Spaniards, a Constituent Assembly was convened after the war and the foundation of a Republic of Cuba was prepared. Four days after the final vote on the Constitution, the Patt Amendment, named after Senator Orville Patt, was incorporated into the Senate as an amendment to the Cuba's Independence Act and confirmed by the House of Representatives another 4 days later. In an annex to the constitution, Cuba should grant the USA a military intervention right and grant them military bases. This was initially rejected by the Constituent Assembly by a majority of 24: 2 votes. After massive US pressure, however, more than 3 months later, a majority of 16:11 votes were cast for the constitution with limited sovereignty. The Republic of Cuba was virtually a protectorate of the USA; However, the Philippines were not independent until 1946, Puerto Rico, Guam and the US Virgin Islands are still outside areas of the United States. On this basis, Cuba was forced on the lease of 23.02.1903 on the Bay of Guantánamo.
In 1934, under President Roosevelt and Cuba's military ruler Batista, the treaty on relations between the US and Cuba was repealed and the Patt amendment was removed from the Cuban constitution. The US gave up its rights and all other military facilities in Cuba; however, the leasing agreement for the Guantánamo base, which excludes a one-sided termination, has been renewed.
On the validity of the contract, the US and Cuba have different legal views. Scientific Service of the German Bundestag comes in its opinion "The lease between Cuba and the US on Guantánamo" to the conclusion that the Patt-Amendment has violated Art. 48-52 of the Vienna Convention on the Law of International Treaties (WÜV) and the lease can be challenged by Cuba. However, many similar late colonial treaties were closed at that time (e.g., Hong Kong 1889, Macao 1887, Panama Canal 1904), which were internationally recognized as valid. Incidentally, the contract of 1903 was renewed 31 years later. Even assuming the nullity of the 1903 treaty, the 1934 treaty may be reinterpreted as a new treaty. Of course, one can argue that there would have been no change in 1934 without the con-testable lease of 1903. Without the occupation of Cuba by the Spaniards in the 16th century, which from today's perspective was also illegal, there would have been no Republic of Cuba. You cannot solve the problems of the future if you look only in the past!
Interesting, however, is Art. II of the lease, which states that the US may use the area "exclusively for use as a bunker and naval base". However, the US violates this provision with the establishment of the prison camp. "Art. 60 para. 1 WÜV provides for a termination of the contract in response to a substantial breach of contract by another contracting party. "(Scientific Services of the German Bundestag, The Lease Agreement between Cuba and the USA on Guantánamo, p. 10, https://www.bundestag.de/blob/414966/6b997a7f4e7eb5575c16bdef9804a515/wd-2-135-06-pdf-data.pdf) The infringement is also significant because of massive human rights violations that the Republic of Cuba does not have to tolerate on its territory. The fact that the base is a part of Cuba was also explicitly confirmed in the lease agreement.
At least for this reason, the US base in Cuba is illegal. However, the Cuban government should call on the US government to immediately close the detention center - perhaps with one month's notice - and subsequently terminate the lease (that it can be annulled anyway) for good cause and clear the entire bay demand. It can then sue the US government for eviction in a US court.
A lawsuit could be politically very embarrassing for the US government. For the camp, the location Guantánamo Bay was chosen so that the US courts are not competent. How-ever, they are responsible for an eviction action, and proof can be taken of the serious breach of contract. Then the US government could only evade the process with a volun-tary return of the base to Cuba. Then the torture camp would close quickly.
Pedro Antonio García, Platt Amendment. Das Protektorat als Republik verkleidet, http://de.granma.cu/cuba/2017-03-02/platt-amendment-das-protektorat-als-republik-verkleidet
Wissenschaftliche Dienste des Deutschen Bundestages, Der Pachtvertrag zwischen Kuba und den USA über Guantánamo, https://www.bundestag.de/blob/414966/6b997a7f4e7eb5575c16bdef9804a515/wd-2-135-06-pdf-data.pdf
Alfred de Zayas, die amerikanische Besetzung von Guantánamo, Institut für Rechtspolitik der Universität Trier, 2005, S. 1, https://www.uni-trier.de/fileadmin/fb5/inst/IRP/ Rechtspolitisches_Forum/28_deZayas_EBook_geschuetzt.pdf