Congress is facing renewed scrutiny over spending related to migrant detention operations at Guantanamo Bay Naval Base, with a Pentagon expenditure exceeding $70 million for the effort, according to a May CBS News report. The figure represents an increase from earlier congressional estimates and comes as lawmakers debate broader immigration enforcement funding.
The operation, known as Operation Southern Guard, marked the first time individuals have been transferred from the U.S. interior to Guantanamo for detention purposes. According to data cited in reports by CBS News and a December congressional report released by Sen. Elizabeth Warren (D-Mass.) and Rep. John Garamendi (D-Calif.), approximately 832 immigrants have been held at the base since February 2025.
The December congressional report found that the Department of Defense obligated well over $2 billion on immigration enforcement in fiscal year 2025, including border security operations and detention activities that diverted funds from military construction projects. That total included authorization for civilian employees to support the Department of Homeland Security through the fall.
The current $70 million-plus figure represents a roughly $20 million increase from what was identified in the December report and approximately $10 million more than figures cited in a joint State Department and Defense Department Inspectors General report released in February. The discrepancy has drawn attention from Democratic lawmakers.
What the Right Is Saying
Supporters of the administration's immigration enforcement posture have defended the use of military facilities for detention purposes, arguing that strong border security measures serve vital national interests. Defense Secretary Pete Hegseth said in February that Guantanamo Bay sends a clear deterrent message to those considering illegal entry: 'If you break the law, if you are a criminal, you can find your way at Guantanamo Bay.'
Conservative voices have emphasized that Congress authorized funding for immigration enforcement and border security operations through standard appropriations processes. Senate Republicans are currently working to provide an additional $72 billion in funding through fiscal year 2029 specifically for the administration's anti-immigrant agenda.
Republicans have pointed to operational justifications for maintaining flexibility in detention capacity, arguing that surge facilities serve as a deterrent even when not fully utilized. The administration has also cited broader national security concerns in defending its immigration enforcement approach, including the deployment of troops to the Southern border and National Guard forces in major cities.
The right has noted that the Pentagon's involvement in immigration operations was authorized under existing legal frameworks, with Defense Department support for DHS operations justified as a matter of interagency cooperation during periods of elevated migration.
What the Left Is Saying
Progressive Democrats and immigrant rights advocates have called for an end to detention operations at Guantanamo, arguing that the base's history and high costs make it unsuitable for immigration detention. Thirty-one members of Congress, led by Rep. Delia Ramirez (D-Ill.), sent letters urging the administration to terminate the program. Over 80 U.S.-based and international civil society organizations have joined those calls.
Sen. Elizabeth Warren stated in releasing her December report that the spending represented a 'blank check' approach to immigration enforcement that lacked proper oversight. The senator has called for greater scrutiny of Pentagon expenditures related to domestic immigration operations.
Yumna Rizvi, senior policy analyst at the Center for Victims of Torture, wrote in an opinion column published by The Hill that detention at Guantanamo represents a 'layer of cruelty' as the administration leverages what she described as the base's history. 'Congress must stop writing blank checks for cruelty,' she argued. She also noted that tents erected to hold 30,000 migrants at a cost of $3 million have gone unused.
The left has pointed to a staff-to-detainee ratio of approximately 100 to 1 at Guantanamo and roughly 600 government employees stationed there as evidence of inefficiency. Advocates argue the resources could be better deployed toward established domestic detention infrastructure.
What the Numbers Show
$170 billion: Total immigration enforcement funding Congress provided to the Trump administration last year through standard appropriations
$72 billion: Additional immigration enforcement funding Senate Republicans are working to authorize through 2029
Over $2 billion: Amount the Department of Defense obligated for immigration enforcement in fiscal year 2025, per the Warren-Garamendi congressional report
Over $70 million: Pentagon spending specifically on migrant detention operations at Guantanamo Bay, per May CBS News reporting
$20 million: Increase from December congressional estimates in current Guantanamo detention costs
832: Number of immigrants transferred to Guantanamo since February 2025 under Operation Southern Guard
30,000: Capacity the tent facilities at Guantanamo were designed to accommodate
600: Approximate number of government employees stationed at Guantanamo for immigration-related operations
100-to-1: Staff-to-detainee ratio cited in reporting on Guantanamo detention operations
780: Total detainees held at Guantanamo since 2002 under post-9/11 military detention program
$500 million+: Historical annual cost of the overall Guantanamo detention facility, according to various government and independent estimates
15: Number of men remaining in indefinite military detention at Guantanamo under the original post-9/11 program
The Bottom Line
Congress faces pressure from both sides as it considers additional immigration enforcement funding. Democrats are seeking cuts or conditions on Guantanamo-related spending, while Republicans maintain that strong enforcement measures require flexible resources.
The $70 million-plus Pentagon expenditure on migrant detention represents a relatively small portion of overall immigration enforcement costs but has generated disproportionate attention due to Guantanamo's controversial history and the base's association with post-9/11 military detention practices. Congressional appropriators will likely face questions about oversight mechanisms for such spending in future budget debates.
What remains unclear is whether the administration plans to maintain, expand or wind down Operation Southern Guard as migration patterns shift. The unused tent facilities raise questions about whether surge capacity was intended primarily for deterrence rather than actual use. Watch for upcoming congressional hearings on Defense Department appropriations and any updated Inspectors General reports on detention operations costs.