Lawfare Podcast Archive: Deploying the Military at the Southern Border, with Chris Mirasola
Aired: November 29, 2025 | Host: Benjamin Wittes | Guest: Chris Mirasola

Episode Overview

This episode dives deep into the legal, political, and practical issues surrounding presidential authority to deploy the military—particularly the National Guard—to the U.S. southern border for immigration enforcement. With renewed calls and campaign promises to use military force for mass deportations, host Benjamin Wittes and guest Chris Mirasola, a legal scholar from the University of Houston Law Center, break down existing frameworks, the Posse Comitatus Act, the history of military involvement in immigration enforcement, the logistics of detention facilities, and the underlying risks to U.S. civil-military relations.

Key Discussion Points & Insights

1. Current Legal Regime and Historical Usage

• National Emergency Status: There is already a standing national emergency regarding drug trafficking, which legally enables the deployment of reservists and National Guard at the border. Both the Trump and Biden administrations have used this framework.
  • "There is a national emergency right now about the drug trafficking crisis... military folks... are all at the southern border, and they're all supporting CBP" (Chris Mirasola, 05:10)
• Role of Military at Border: The military at the southern border primarily supports Customs and Border Protection (CBP) but does not engage directly in law enforcement (arresting or detaining migrants).

2. Proposed Changes Under Trump’s Plans

• Potential Expansion: Trump’s public statements suggest plans for deploying the military not just as support, but for direct law enforcement actions—arresting and detaining migrants.
  • "Everything that we've seen suggests... some number of National Guard will likely be doing a law enforcement function in this second Trump administration." (Chris Mirasola, 08:40)
• Legal Gray Area: The Posse Comitatus Act generally bars military law enforcement in the U.S., but National Guard in "hybrid" state-federal duty can bypass this restriction—a "gigantic loophole."
  • "The Posse Comitatus act... doesn't apply to them. This is... a gigantic loophole." (Chris Mirasola, 11:51)

3. Precedent and Uniqueness of Proposed Deployments

• Historical Context: While National Guard have supported border operations in the past (Bush, Obama, Trump), their direct involvement in law enforcement at the border would be unprecedented in recent decades.
  • "Having National Guard in this hybrid duty status at the southern border would not be unprecedented. Having them... doing significant law enforcement functions would be unprecedented." (Chris Mirasola, 13:28)
• Broader Implications: There is a risk of normalizing military involvement in daily U.S. law enforcement, potentially spilling over into non-immigration policy areas.

4. Risks and “Freakout” Calibration

• Scale & Uncertainties: The degree of public concern should be modulated. The precedent is concerning but, in the near term, likely changes are incremental—not revolutionary or immediate.
  • "It's kind of like… a 5 to 7 [out of 10]... What remains unclear is the extent of the law enforcement mission that these National Guard folks will be given." (Chris Mirasola, 15:50)
• Best-Case & Worst-Case Scenarios:
  • Best case: National Guard act as reinforcements, responding when CBP is overwhelmed.
  • Worst case: Military takes front-line role, detaining migrants in new facilities—a practice for which they lack both experience and legal certainty.

5. Detention Facility Logistics

• Authority to Build: A national emergency could allow rapid construction of detention centers using DoD resources, as seen with the border wall. But practical constraints (funding, contracting, supply chain) mean these are not “overnight” projects.
  • "It'll… take a couple weeks... to find the people. Right. In the requisite numbers." (Chris Mirasola, 27:31)
  • "Figuring out… finding the money and then being able to actually deploy the money to do something takes a substantial amount of time." (Chris Mirasola, 30:37)
• Interior vs. Border Enforcement: DoD cannot legally assist with interior ICE roundups—statutory authorities are specific to border missions.

6. Litigation as a Slowing Factor

• Court Hustle: Any executive order will spur immediate legal challenges. While the Supreme Court is unlikely to prohibit action, lower court injunctions will drag out the timeline.
  • "It's relatively easy to find a judge… who would enjoin DOD from… engaging in the construction process." (Chris Mirasola, 33:21)

7. Timeline & Likely Outcomes

• Slow Ramp, Not Blitz:
  • 1–2 months post-declaration: Some increase in Guard numbers at the border, marginal functions augmented.
  • Within 6 months: Unlikely to see large-scale, military-run detention facilities due to legal, logistical, and bureaucratic delays.
  • "I think within one to two months, you have some degree, probably not insubstantial, but also probably not, you know, 10,000 additional military at the southern border assisting in perhaps marginally more functions than they are currently." (Chris Mirasola, 36:30)
  • "I'd be surprised to see much in the way of… that part of the equation in the first six months…" (Chris Mirasola, 37:55)

8. Broader Concerns: Sliding Toward Domestic Military Normalization

• Slippery Slope: Regularized border deployments could make domestic military use more 'normal' elsewhere.
  • "Once we get used to even relatively more action at the southern border, it becomes… easier to use the military in aspects of daily life within the United States where we haven't seen a substantial role…" (Chris Mirasola, 41:22)

9. The Insurrection Act: Legal “Nuclear Option”

• Extraordinary Powers: The Insurrection Act gives the president carte blanche to use regular military forces for domestic law enforcement, with few procedural hurdles.
  • "The Insurrection act… authorizes the President… to use the military much more broadly… to suppress domestic unrest. Do law enforcement… as any kind of federal law enforcement agency." (Chris Mirasola, 41:50)
• Why Not Immediate Use?: Despite its breadth, political and practical risks make it unlikely to be invoked first—though its use cannot be ruled out.

Notable Quotes & Memorable Moments

• On the gigantic loophole for National Guard:

  "Because they're not part of the armed forces, The Posse Comitatus act just doesn't apply to them. This is… a gigantic loophole."
  (Chris Mirasola, 11:51)

• On “freakout” level:

  "It's kind of like if we're on, like, one to ten scale, probably somewhere around, like, the five to seven varieties…"
  (Chris Mirasola, 15:50)

• On why swift action is unlikely:

  "A lot of nothing for a significant period of time… Even if the president invokes the Insurrection Act… National Guard folks, like, have a day job…"
  (Chris Mirasola, 27:31)

• On potential “slippery slope”:

  "Once we get used to even relatively more action at the southern border… it becomes practically, and I also think just politically, easier to use the military in aspects of daily life…"
  (Chris Mirasola, 41:22)

• On the Insurrection Act as a last resort:

  "It is also significantly like the nuclear option, right? It is the authority that provides the President the most expansive authority to use the military in the United States."
  (Chris Mirasola, 43:38)

Important Segment Timestamps

• Overview of current border military deployments: 05:10–06:22
• Legal framework for presidential border powers: 07:12–11:11
• Hybrid National Guard status loophole: 11:11–12:47
• Discussion of precedents and “freakout” meter: 13:18–16:01
• Risks of deploying military for law enforcement: 16:13–18:22
• Detention facility logistics and complications: 19:06–20:06, 29:51–32:43
• Litigation’s role in slowing deployments: 32:43–35:26
• Insurrection Act as legal nuclear option: 41:22–44:41

Summary Takeaways

• The standing national emergency already allows military support at the border, mostly in detection/monitoring, not law enforcement.
• Trump’s campaign rhetoric suggests a real chance of expanding the military's role into direct law enforcement—something without precedent in the border context for the past half-century.
• The current legal architecture (through the National Guard loophole) enables this, though practical, political, and (ultimately) legal constraints remain significant.
• Immediate, large-scale changes are unlikely; expect gradual increases in military involvement, limited by logistics, statutory specifics, and litigation.
• The normalization of domestic military deployments—to the border or elsewhere—remains the longer-term civil-military relations concern.

For those seeking a sober, detailed look at how presidential authority, military statutes, and immigration enforcement intersect, this episode provides a thorough, non-alarmist breakdown.