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Hirono, Warren Press Defense Secretary Hegseth on Cost and Military Readiness Impact of Deploying Troops to Southern Border, Guantanamo Bay

Senators: “DoD’s new immigration operations — which the Trump administration is planning at an unprecedented scale — threaten to burden the Department’s resources and undermine our national security.”

WASHINGTON, DC – Today, U.S. Senator Mazie K. Hirono (D-HI), a senior member of the Senate Armed Services Committee and ranking member of the Subcommittee on Readiness and Management Support, joined Senator Elizabeth Warren (D-MA) in writing to Secretary of Defense Pete Hegseth regarding the military’s recent increased deployment of active-duty forces to the southern border and Naval Station Guantanamo Bay, and the Department of Defense’s (DOD) new involvement in immigration detention and deportation.

On his first day in office, President Trump signed an Executive Order directing the United States Northern Command (NORTHCOM) to “seal the borders” and “to provide steady-state southern border security.” On January 29, President Trump directed DOD to “expand the Migrant Operations Center at Naval Station Guantanamo Bay to full capacity” of 30,000. As a result, NORTHCOM has deployed about 2,000 active-duty troops to the southern border, bringing the total under DOD’s command to over 4,000. These deployments have drawn from numerous Army and Marine Corps units from across the country, and DOD has required the 10th Mountain Division from Fort Drum, New York to oversee these units. In the near term, the Trump administration is reportedly considering deploying up to 10,000 troops to the southern border — double the scale of DOD’s border deployment in 2019 and 2020. That number could grow; during President Trump’s first term, then-Secretary of Defense Mark Esper said Stephen Miller (now White House Deputy Chief of Staff) said that “[w]e need a quarter-million troops” at the southern border.

Following Immigration and Customs Enforcement’s (ICE) reversal of its policy prohibiting the use of military aircraft to deport migrants, DOD has operated over 10 deportation flights around the world. To support President Trump’s expansion order, SOUTHCOM has deployed over 500 Marines to Naval Station Guantanamo, and the Trump Administration has not ruled out detaining women and children there. A former Pentagon official estimates that these operations would “quickly skyrocket into tens of millions, if not hundreds of millions, of dollars.”

“[DoD’s] new immigration-related operations place significant—and unnecessary—burdens on DoD resources, personnel, and readiness,” wrote the senators. 

The military aircraft now used for deportations, for example, cost far more than the commercial and chartered flights that ICE normally uses for deportations. Using C-17 military planes costs taxpayers over $28,000 per flight hour for a single deportation, compared to $8,577 per flight hour on civilian aircraft alternatives that ICE often uses. Last week, a C-17 that deported 104 people to India cost $2.5 million—over $24,000 per person. Similarly, ICE’s contract for Guantanamo’s migrant operations center requires it to pay a staggering $272,000 per detention bed, compared to around $57,00 per bed at ICE facilities within the United States. 

DOD has yet to provide a realistic estimate of how much these new operations will cost. During President Trump’s first term, when DOD deployed troops to the border between FY2018 and FY2020, the Department estimated that its border operations would total $1 billion in unreimbursed costs. The Government Accountability Office (GAO) later found that “DOD did not present reliable cost estimates.” Since then, DOD has not implemented any of GAO’s recommendations for improving how it estimates the cost of assisting DHS’s immigration operations.  

DOD’s growing participation in DHS immigration operations will pose serious costs for units’ readiness. The Secretary of Defense discontinued part of DOD’s border operations between 2018 and 2020 after finding that “continued support for the mission would negatively affect military readiness and morale.” The commandant of the Marine Corps warned at the time that the operation posed an “unacceptable risk to Marine Corps combat readiness and solvency,” as a result of separated units and canceled training exercises. 

“Likewise, we are concerned about how these operations may impact servicemembers’ morale. In recent years, DoD personnel who deployed to the border have reported dangerously low morale, driven by an unclear mission, isolation, boredom, poor accommodations, and more,” wrote the lawmakers. “Poor morale even contributed to a series of suicides by members of the Texas National Guard who deployed to the southern border.”

“[T]he Trump administration is militarizing the country’s immigration enforcement system in an apparent attempt to signal toughness. But this political stunt will come at a high cost; it risks diverting DoD’s resources away from its vital mission in ways that compromise our national security,” the senators concluded. 

The senators requested that DOD provide more clarity about troop deployment to the border and anticipated costs by February 27, 2025. 

The full text of the letter is available here and below.

Dear Secretary Hegseth:

We are concerned about the Department of Defense’s (DoD) immigration-related operations at the southern border and at Naval Station Guantanamo Bay — including the implications of these operations for the military’s budget, readiness, and morale. DoD’s support for the Department of Homeland Security (DHS) has been expensive for American taxpayers, with some DoD expenses costing over three times more than when DHS performs the same function, while also posing “an unacceptable risk” to units’ readiness. DoD’s new immigration operations — which the Trump administration is planning at an unprecedented scale — threaten to burden the Department’s resources and undermine our national security. To better understand those risks, we write to request additional information about these operations.

On his first day in office, President Trump signed an Executive Order (EO) directing the United States Northern Command (NORTHCOM) to “seal the borders” and “to provide steady-state southern border security.” Then on January 29, President Trump directed DoD to “expand the Migrant Operations Center at Naval Station Guantanamo Bay to full capacity” of 30,000.

In response, over the past four weeks, NORTHCOM has deployed roughly 2,000 active-duty troops to the southern border, drawing from numerous Army and Marine Corps units and directing the 10th Mountain Division from Fort Drum, New York to oversee the units. Those troops supplemented the 2,500 National Guard members already stationed at the border, bringing the total under DoD’s command to over 4,000. DoD leaders have made clear that “there will be very likely additional missions, this is just the start.” In the near term, the Trump administration is reportedly considering deploying up to 10,000 troops to the southern border—double the scale of DoD’s border deployment in 2019 and 2020. That number could grow; during President Trump’s first term, Stephen Miller (now White House Deputy Chief of Staff) allegedly asserted that “[w]e need a quarter-million troops” at the southern border.

Furthermore, DoD has operated over 10 deportation flights—including to Guatemala, Ecuador, India, and Guantanamo—following Immigration and Customs Enforcement’s (ICE) reversal of its policy against using military aircraft to deport migrants. Meanwhile, DoD has supplied facilities to assist DHS immigration enforcement operations. Within the United States, DoD agreed to temporarily detain migrants at the Buckley Space Force Base in Colorado on behalf of ICE. At Guantanamo, SOUTHCOM is in the process of expanding the Migrant Operations Center’s (MOC) capacity to 30,000—up from its current maximum capacity of just 120. Migrants are also being held in Guantanamo’s “Camp 6” prison, which previously held War-on- Terror detainees. DHS has not ruled out detaining women and children at Guantanamo. So far, 500 Marines have been ordered to deploy to Guantanamo, with potentially more to come. DoD has been noncommittal about how long they will stay; one spokesperson noted “mass migration is unpredictable, and the extent of U.S. military support will be determined as events unfold.”

NORTHCOM’s and SOUTHCOM’s new immigration-related operations place significant—and unnecessary—burdens on DoD resources, personnel, and readiness. DoD has estimated that its southern border operations will cost almost $1 billion over just eight months, through the end of this fiscal year, compared to its estimate of $1 billion over three years during the first Trump administration. DoD does not yet have a cost estimate for its new Guantanamo operations, but a former Pentagon official warned that “[t]he total cost for this [Guantanamo operation] would quickly skyrocket into tens of millions, if not hundreds of millions, of dollars.”

Much of this cost is avoidable. For example, DoD is deporting migrants on C-17 military aircraft, which cost far more than the commercial and chartered flights that ICE normally uses for deportations. Taxpayers pay over $28,000 per flight hour for a single deportation on a military C-17 plane, compared to $8,577 per flight hour on civilian aircraft alternatives that ICE often uses. Similarly, ICE pays contractors over $272,000 per detention bed to operate Guantanamo’s MOC, compared to an average of around $57,00 per bed at ICE facilities within the United States.

Perhaps more concerning, DoD may not have a realistic estimate of how much these new operations will cost. When DoD deployed to the border between FY2018 and FY2020 during President Trump’s first term, the Department estimated that its border operations would total $1 billion in unreimbursed costs between FY2018 and FY2020. The Government Accountability Office (GAO) later found that “DOD did not present reliable cost estimates . . . that would allow the Secretary to gauge how providing support could affect the department’s budget.” DoD neglected to include entire categories of expenses in its estimates, such as the cost of DoD installations to support military personnel and National Guard member benefits. The Department also failed to accurately report its costs to Congress. Since then, DoD has not implemented any of GAO’s recommendations for improving how it estimates the cost of assisting DHS’s immigration operations.

Beyond budgetary costs, DoD’s growing participation in DHS immigration operations will pose serious costs for units’ readiness. The Defense Secretary discontinued part of DoD’s border operations between 2018 and 2020 after finding that “continued support for the mission would negatively affect military readiness and morale.” The Commandant of the Marine Corps had warned that the operation posed an “unacceptable risk to Marine Corps combat readiness and solvency.” For example, DoD sent Blackhawk helicopters to the border, “separate[ed] units in order to assign a portion of them to the southwest border mission,” and canceled training exercises — all of which reduced the readiness of the impacted units. Again, GAO found that DoD had underestimated these costs, approving border deployments with “limited information about how providing the requested capabilities would affect readiness.” And again, DoD has not implemented any of GAO’s recommendations for improving its assessment of how border operations impact readiness. This track record casts doubt on your prediction that the current border operations will in fact “contribute[] to readiness.”

Likewise, we are concerned about how these operations may impact servicemembers’ morale. In recent years, DoD personnel who deployed to the border have reported dangerously low morale, driven by an unclear mission, isolation, boredom, poor accommodations, and more. Poor morale even contributed to a series of suicides by members of the Texas National Guard who deployed to the southern border after 2020. As mentioned above, the Defense Secretary scaled back border operations in 2019 in part because of how the mission was harming troops’ morale.

In all, the Trump administration is militarizing the country’s immigration enforcement system in an apparent attempt to signal toughness. But this political stunt will come at a high cost; it risks diverting DoD’s resources away from its vital mission in ways that compromise our national security. We request answers to the following questions by February 27, 2025:

U.S.-Mexico Border Operations

  1. Please provide a complete list of units deployed to the southern border and the estimated length of deployment for each.
  1. How is NORTHCOM tracking border support activity costs and ensuring the accuracy of cost tallies?
  1. Describe how DoD is assessing the impact of southern border operations on troops’ readiness.
    1. Have any training exercises been delayed or canceled due to the recent deployments to the southern border? Please provide the dates and types of any affected training exercises and explain which units were impacted.
    2. Is DoD separating units when sending personnel to the border? If so, please explain the reasoning, given evidence of how doing so between 2018-2020 harmed units’ readiness.
  1. How, if at all, is NORTHCOM monitoring the impact of the border deployment on troops’ morale?
  1. Please list all National Guard forces that are currently participating in southern border operations and the authority under which they have deployed.
  1. GAO previously found that “DoD has not defined what it considers to be a manageable impact on readiness.” How is DoD determining when an anticipated impact on readiness is “manageable”?
  1. What was the total cost of DoD’s border deployment between 2018-2020?
  1. What does NORTHCOM project the total cost of border operations will be this calendar year?
    1. Please explain the assumptions underlying that estimate.
    2. Provide the total operational costs of DoD’s border deployment since January 20, 2025.
    3. What budgetary account will be used to pay for the operations?
    4. Which expenses, if any, is DoD paying for on a non-reimbursable basis? If DoD is waiving reimbursement for any expenses under 10 U.S.C. § 277, provide the justification for doing so.
  1. Are any noncitizens currently being held at the Buckley Space Force Base in Colorado?
    1. If so, please describe the authority under which they are being held and the protocol for them to access legal counsel.
  1. Is DoD considering using other military bases in the United States for detention operations?
  1. Provide a full list of tasks to which active-duty forces will be assigned, along with a summary of functions to date and a summary of upcoming functions DoD troops will engage in.
  1. What are the rules of engagement that govern each unit deployed to the border?
  1. Are servicemembers authorized to use force at the border?
    1. In 2020, the DoD Inspector General found that some troops did not receive Standing Rules for the Use of Force (SRUF) training. What percentage of troops currently deployed to the border have completed training on when and how they can use force? Please describe the training they receive on the authorization of military force.
    2. Are servicemembers under DoD’s command authorized to use force against unarmed civilians at the border?
    3. Under what circumstances, if any, are servicemembers under DoD’s command authorized to make arrests at the border?
  1. How does DoD handle encounters with citizens at the border?

Guantanamo Operations

  1. Please describe SOUTHCOM’s precise role(s) in Guantanamo’s migrant detention operations.
    1. How, if at all, are DoD personnel directly involved in the detention of any migrants at Guantanamo.
    2. Has DoD (or any of its components) signed any memoranda of understanding or similar agreements with DHS regarding the detention of migrants at Guantanamo? Please provide a copy of any agreements if so.
  1. Describe DoD’s precise role at the MOC and Camp 6 and how this role is currently projected to evolve.
    1. There are reports that DoD personnel are guarding migrants at Camp 6. Please explain in detail who is currently guarding Camp 6 and whether there are plans to change the personnel stationed at Camp 6.
    2. Are migrants at the MOC or Camp 6 free to leave or are they being formally detained? If they are detained, under what legal authority are migrants being detained at Guantanamo’s Camp 6?
  1. How, if at all, is SOUTHCOM monitoring the impact of the Guantanamo deployment on troops’ morale?
  1. Describe how DoD is assessing the impact of Guantanamo MOC operations on troops’ readiness.
  1. Has DHS informed DoD of whether Guantanamo’s MOC will be used to hold any migrants who have not received final orders of removal?
    1. Have any migrants currently at the MOC not received final removal orders?
  1. What does SOUTHCOM project the total cost of Guantanamo’s MOC operations will be this fiscal year? If no single cost estimate is available, please provide a series of cost estimates based on the different scenarios for which DoD is planning.
  1. GAO has found that DHS has detained U.S. citizens after mistaking them for foreign nationals. What steps, if any, does DoD take to confirm the identity of an individual before taking them into custody at a military facility or on a military aircraft?
  1. What is DoD’s timeline for constructing permanent structures at the MOC and how long do you anticipate migrants will be held in soft-sided facilities?
  1. What term is being used to describe noncitizens deported from the United States to Guantanamo?
  1. What is DoD’s plan for migrants held at Guantanamo whose home country will not accept their repatriation?
  1. What is DoD’s plan for evacuating the MOC during extreme weather events?
  1. Please provide a summary of the age and gender of migrants currently being held at Guantanamo’s MOC.
    1. Has DoD been informed of any plan to detain women or children at Guantanamo?
  1. What government entities, if any, will conduct on-site inspections of Guantanamo’s MOC and Camp 6, and at what frequency? Will they publicly report on findings?
  1. Has DoD received requests for access to the MOC or Camp 6 by legal service providers, humanitarian organizations, press, or other members of the public? How have requests been handled?
    1. Describe DoD’s plans for facilitating migrants’ access to counsel.
    2. Has DHS requested that SOUTHCOM facilitate confidential legal phone calls or legal visits?
  1. What steps is DoD taking to make the MOC and Camp 6 facilities habitable for the number of migrants expected to be held at Guantanamo.
    1. Are any migrants currently housed in spaces with black mold, leaks, electrical fires, or other maintenance issues?
  1. As of the date of your response, what is the current capacity of the MOC at Guantanamo?
    1. How long does SOUTHCOM anticipate it will take DoD to complete the first phase of the MOC expansion to 2,000 migrants?
    2. What is the maximum number of migrants for whom Guantanamo’s MOC currently has the capacity and resources to provide sanitary facilities, medical care, food, and potable water?
  1. Please explain the standards of care that DoD personnel are bound to provide at Guantanamo and provide a copy of DoD’s protocol, if any, on standards of care.

Thank you for your attention to this important matter.

Sincerely,

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