Wiener Übereinkommen über das Recht der Verträge
The long-term lease of Guantanamo Bay Naval Base continues. The Cuban government since 1959 has strongly denounced the treaty as a violation of Article 52 of the 1969 Vienna Convention on the Law of Treaties, which declares a treaty void if procured by the threat or use of force. However, Article 4 of the Vienna Convention states that its provisions shall not be applied retroactively.