Can the United States Send Undocumented Immigrants to Guantánamo Bay?

The Trump administration’s crackdown on undocumented immigrants includes a plan to transport potentially thousands to Guantánamo Bay. It is likely to spur international condemnation and a range of legal challenges.
February 4, 2025 2:12 pm (EST)

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John B. Bellinger III is adjunct senior fellow for international and national security law at the Council on Foreign Relations.
What is President Trump trying to do with Guantánamo?
Last week, President Donald Trump signed a memorandum to the secretaries of defense and the homeland security directing them “to take all appropriate actions to expand the Migrant Operations Center at Naval Station Guantánamo Bay to full capacity to provide additional detention space for high-priority criminal aliens unlawfully present in the United States.”
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Trump wants to use part of the base that has housed migrants interdicted in the Caribbean to now hold certain undocumented immigrants arrested in the United States. To be clear, the Migrant Operations Center is a different part of the base than the one that has been used to detain terrorism suspects since 2002 and that resulted in widespread international criticism of the United States for placing detainees in a legal “black hole.”
Presumably, Trump would use the new facility to hold unauthorized immigrants pending their deportation to their countries of nationality. However, Trump said in a White House press conference the day he issued the directive that the expanded facility would be used to “detain the worst criminal illegal aliens threatening the American people. Some of them are so bad we don’t even trust the countries to hold them because we don’t want them coming back, so we're going to send them out to Guantánamo.” Although this suggests that Trump may not be willing to return some detainees to their home countries, Secretary Homeland Security Kristi Noem has said that the administration does not plan to hold detainees “indefinitely” at Guantánamo.
How many people does the administration expect to detain in the new facility?
The memorandum does not specify how many people the facility should hold, but Trump said he instructed the Departments of Defense and Homeland Security to begin preparing “the thirty thousand-person migrant facility at Guantánamo Bay.” However, Trump may simply have been referring to the fact that the migrant facility had processed roughly that number of migrants during two different periods under previous presidential administrations.
How has the United States used the Guantánamo Bay naval facility for detention purposes?
The United States has leased forty-five square miles on the southeastern tip of Cuba for use as a naval base since 1903. Because the lease agreement requires the consent of both the United States and Cuba to terminate it, the facility has endured for 122 years, even though the Cuban government has objected since 1959.
From 1991 to 1993, and again from 1994 to 1996, the United States used a part of the base to house large numbers of Haitians and Cubans who fled their countries on boats and rafts to claim asylum in the United States. The refugees and migrants were interdicted by the Coast Guard at sea and taken to Guantánamo for processing. The Migrant Operations Center reportedly processed more than thirty thousand Haitians and more than thirty thousand Cubans during each of the two waves, although it does not appear that more than twelve thousand were held at any single period. The refugees and migrants resided in tent cities surrounded by razor wire; the facilities were criticized by human rights groups for squalid conditions.
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Why does Trump want to transfer unauthorized immigrants to Guantánamo? Why not simply detain them in the United States pending their deportation?
It’s not entirely clear why Trump wants to use Guantánamo for this purpose. He may be doing it more for shock value and deterrence than for reasons of practical necessity. It would be extremely costly and likely take a year or more to expand the Migrant Operations Center to hold up to thirty thousand people.
The U.S. government would then need to fly the detainees to Cuba and feed and care for them for the length of their detention. It would potentially be faster and cheaper to house undocumented immigrants at federal facilities in the United States. Trump and his advisers may be calculating that the threat of transfers to Guantánamo will persuade undocumented immigrants arrested in the United States (or considering entering the United States) to return to their countries and persuade their home countries to take them back.
How much would such an expansion cost?
The Migrant Operations Center expansion is likely to cost hundreds of millions of dollars and would require specific congressional appropriation. Given the high cost and past controversies surrounding detention at Guantánamo, as well as the narrow Republican majorities in Congress, it is possible that Congress may refuse to foot the bill for an expansion of the facility.
Will the transfer and detention of unauthorized immigrants to Guantánamo result in legal challenges?
Without a doubt. Unauthorized immigrants transferred (or threatened with potential transfer) from the United States to Guantánamo will file a vast array of legal challenges, providing a lot of business for the courts. Haitian and Cuban refugees previously held on Guantánamo—as well as many of the terrorism suspects—filed numerous suits challenging the detention and conditions, several of which were ultimately heard by the Supreme Court.
For example, in Boumediene v. Bush, the Supreme Court held that terrorism detainees held at Guantánamo enjoyed a constitutional right to habeas corpus—even though the naval base is not part of the United States—because the U.S. government effectively controls Guantánamo Bay. The Supreme Court held in another case, Zadvydas v. Davis (which did not involve Guantánamo), that the Constitution does not permit “indefinite detention” of undocumented immigrants who are ordered deported from the United States, even when their home countries refuse to accept them. Any attempt by the Trump administration to detain undocumented immigrants at Guantánamo for lengthy periods will almost certainly result in lawsuits under these precedents.
Moreover, it is important to emphasize that all the prior cases filed by persons detained at Guantánamo involved people detained outside the United States who were then taken to Guantánamo. Individuals arrested in the United States and transferred out will be able to file additional claims. Indeed, it is possible that federal courts may prohibit the transfer of persons from the United States to Guantánamo, given that it is not part of the United States.
Unauthorized immigrants detained in the United States also have a right to counsel and to be visited by a consular official from their country of nationality. Such immigrants may claim that their transfer to Guantánamo will interfere with their ability to exercise these rights.
What about international reaction?
Guantánamo Bay became a lightning rod for international criticism after the George W. Bush administration began to use the facility to detain 779 suspected terrorists captured in Afghanistan and elsewhere following the attacks on the United States on September 11, 2001. The Trump administration will likely face similar criticism as well as potential international legal challenges if it moves forward to open a large detention facility, especially if conditions are poor, detentions are lengthy, and detainees lack access to counsel or consular officials.
What will be the impact of an expansion of Guantánamo on the terrorism suspects there?
If Trump does in fact transfer thousands of unauthorized immigrants to Guantánamo, their conditions and legal challenges may greatly overshadow the situation of the fifteen remaining terror suspects held on a different part of the base. The terror suspects, some of whom have been charged with war crimes and are facing trials in military commissions, are held by the U.S. Navy under the customary laws of war, whereas any unauthorized immigrants transferred to Guantánamo would be held by the Department of Homeland Security pursuant to U.S. immigration statutes.
President Barack Obama had ordered the closure of the terrorism detention facility at Guantánamo but was not able to do so. Similarly, President Joe Biden stated at the beginning of his presidency that he hoped and expected to close the terrorism detention facility, but he also did not succeed. However, Biden did reduce the number of detained terror suspects from forty to fifteen, including through a transfer of eleven Yemeni detainees to Oman in early January 2025.
For more than a decade, Congress has included a provision in the National Defense Authorization Act prohibiting the use of appropriated funds to transfer any Guantánamo detainees to the United States, which both Obama and Biden objected to. Indeed, it is somewhat surprising that Biden, as a lame duck, did not simply transfer the remaining detainees to a military prison in the United States, based on a rationale that Congress’ prohibition is an unconstitutional infringement on his authority as commander in chief. Biden may have calculated that if he had done so, President Trump might simply have transferred the detainees back to Guantánamo.
This work represents the views and opinions solely of the author. The Council on Foreign Relations is an independent, nonpartisan membership organization, think tank, and publisher, and takes no institutional positions on matters of policy.