Doesn't Cuba have a lease agreement with the Americans signed in 1903 and renewed in 1934 for Guantanamo bay?
The United States assumed territorial control over the southern portion of Guantánamo Bay under the 1903 Cuban–American Treaty.[1] The United States exercises complete jurisdiction and control over this territory, while recognizing that Cuba retains ultimate sovereignty. The current government of Cuba regards the U.S. presence in Guantánamo Bay as illegal and insists the Cuban–American Treaty was obtained by threat of force and is in violation of international law. Some legal scholars judge that the lease may be voidable
- Wikipedia
the great beholder of justice - USA does not recognize International Court of justice ..and therefore no case can be contested against US .
Opinio Juris: Cuba, the Guantanamo Treaty, and the International Court of Justice