The following is the Aug. 1, 2022, Congressional Research Service report, Naval Station Guantanamo Bay: History and Legal Issues Regarding Its Lease Agreements.
From the report
This report briefly outlines the history of the U.S. Naval Station Guantanamo Bay, Cuba, its changing relationship to the surrounding community, and its heightened importance due to military operations in Afghanistan. The report also explains in detail the legal status of the lease of the land on which the naval station stands, the statutory and treaty authorities granted to the President with regard to any potential closure of the naval station, and the effects on such a closure that Cuba sanctions laws might have.
At the end of the Spanish-American War in 1898, the Spanish colonies of Cuba, Puerto Rico, Guam, and the Philippines transitioned to administration by the United States. Of these four territories, only Cuba quickly became an independent republic. As a condition of relinquishing administration, though, the Cuban government agreed to lease three parcels of land to the United States for use as naval or coaling stations. Naval Station Guantanamo Bay, Cuba, was the sole installation established under that agreement. The two subsequent lease agreements signed in 1903 acknowledged Cuban sovereignty, but granted to the United States “complete jurisdiction and control over” the property so long as it remained occupied.
The prominence of Naval Station Guantanamo Bay rose briefly during the Haitian refugee and Cuban migrant crises of the early 1990s. At one point in late 1994, the migrant population of the naval station approached 45,000. However, by the end of January 1996, the last of these temporary residents had departed.
The naval station’s return to prominence arose due to the establishment of facilities to house a number of wartime detainees captured during military operations in Afghanistan and elsewhere. This practice began in early 2002 with the refurbishment of some of the property formerly used to house refugees and was expanded to more substantial housing that is operated by Joint Task Force-Guantanamo, a tenant for which the naval station provides logistical support. Additional temporary facilities were eventually constructed on a disused naval station airfield for use by the military commissions created to try detainees.
The 1903 lease agreements between the governments of Cuba and the United States are controlled by the language of a 1934 treaty stipulating that the lease can only be modified or abrogated pursuant to an agreement between the United States and Cuba. The territorial limits of the naval station remain as they were in 1934, unless the United States abandons Guantanamo Bay or the two governments reach an agreement to modify its boundaries. While there appears to be no consensus on whether the President can modify the agreement alone, Congress is empowered to alter by statute the effect of the underlying 1934 treaty. There is no current law that would expressly prohibit the negotiation of lease modifications with the existing government of Cuba, but the House of Representatives passed a prohibition on carrying out such a modification without congressional approval as part of the National Defense Authorization Act (NDAA) for FY2017 (P.L. 114-328). This prohibition has been extended in subsequent years through FY2022.
As for “abandoning” the naval station, there appears to be no statutory prohibitions against closing an overseas military installation. Nevertheless, Congress has imposed practical impediments to closing the naval station by, for example, restricting the transfer of detainees from Guantanamo to foreign countries and banning their transfer to the United States. The existence of various sanctions imposed upon Cuba may also impede closing Naval Station Guantanamo Bay by making it difficult to give or sell any property to the Cuban government.
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