The U.S. has breached Guantanamo agreement
The United States leased Guantanamo from Cuba after helping Cuba become independent from Spain. The 1903 lease for Guantanamo restated the understanding, first made in Article VII of the Platt Amendment, that, for its own defense, the government of Cuba will sell or lease to the United States lands necessary for coaling or naval stations. We explicitly undertook the responsibility to protect Cuba, which was a reaffirmation of our duty under the Treaty of Paris. The invasion in 1961 and the ongoing blockade are material breaches of that understanding.
We have no legal right to occupy Cuban lands by virtue of a lease that we have unilaterally abrogated.