(From left to right) Maj. Steve Warburton, then-MAJ Chris Chatelain,
Maj. James Trescothic-Martin, and Capt. Kathleen Brook attend the
British Army Legal Services 75th Anniversary Dinner in London, England.
(Photo courtesy of author)
What’s It Like?
Robo Gen1
from a Legal Exchange Officer in the United Kingdom
By Lieutenant Colonel Christopher M. Chatelain
The U.S. Army Judge Advocate General’s (JAG) Corps has more than 9,700
active duty, Reserve, National Guard, and civilian attorneys, legal
administrators, and paralegals.2
Of this population, only four serve as legal exchange officers, with
three of these positions created in the past five years.3
Two of those exchange positions help maintain the “special
relationship”4
between the United States and the United Kingdom (U.K.). Not
surprisingly, the JAG Corps’s small but growing prioritization of
exchange officers comes at a time when the Department of Defense placed
increased importance on interoperability with allies and partners.5
In an era of heightened geopolitical competition between major powers,
adversary exploitation of rapidly evolving domains and technologies, and
instability from transboundary challenges,6
unity of effort between allies and partners has never been so complex or
important for U.S. national security interests. This article
Seeks to demystify legal exchange officer positions—explaining
how and why the Military Personnel Exchange Program (MPEP) works,
highlighting how the JAG Corps leverages legal exchange officers, and
then illustrating how these efforts translate into legal
interoperability by way of example with the British Army Legal Services
(ALS).
U.S. law and policy authorize and govern U.S. exchange officer
positions. Exchange officers typically serve as part of a reciprocal,
one-for-one exchange of U.S. and partner-nation army personnel.7
Section 311 of Title 10 of the U.S. Code creates The Defense Personnel
Exchange Program (DPEP) as a security cooperation program permitting
mutual exchange of defense personnel.8
Based on this authorization, the Secretary of Defense delegated
authority to administer the MPEP, a component of DPEP, to the Service
secretaries via Department of Defense Directive 5230.20.9
Based on this delegation, the U.S. Army governs its contribution to the
MPEP through Army Regulation 614-10.10
The MPEP has three primary purposes to help achieve national security
cooperation goals and combatant commanders’ theatre campaign plans.
First, the MPEP strengthens alliances and coalitions by building partner
capacity and maintaining or enhancing friendly relationships.11
Second, the MPEP increases U.S. and partner-nation cooperation by
integrating U.S. and partner-nation personnel.12
Third, the program prepares U.S. officers and noncommissioned officers
for future assignments in support of multinational operations.13
Many stakeholders have responsibilities related to executing the MPEP.
The deputy chief of staff (DCS), G-3/5/7 has general staff
responsibility for the Army MPEP.14
The Army Service Component Commands (ASCCs) develop, plan, and integrate
Army exchange programs that support their combatant commanders’ theatre
campaign plan.15
Through the ASCCs, the DCS, G-3/5/7 serves as the lead agent for
negotiating MPEP memoranda of agreement (MOAs) with partner
nations.16
Once the DCS, G3/5/7 establishes a country program, U.S. Army Human
Resources Command (HRC) selects and assigns U.S. Army personnel for the
MPEP positions.17
Positions are nominative, and HRC must ensure that MPEP nominees satisfy
the selection criteria outlined in the exchange program’s corresponding
MOAs.18
Once HRC identifies nominees, the ASCCs forward their information to the
partner/host nation for approval or disapproval.19
For Army legal exchange officers, the Talent Management Office performs
these duties for HRC.20
Simultaneously, partner nations’ military attachés submit their Army
exchange personnel nominees to the recipient Department of the Army (DA)
command and through the DCS, G-2 for approval.21
Once nations agree upon specific exchange personnel, ASCCs have overall
responsibility for MPEP coordination and support activities within their
combatant commands’ area of responsibility.22
Recognizing the importance of allies and partners, the JAG Corps
leverages the MPEP to enhance legal interoperability. The JAG Corps
Strategy highlights that “[a]lliances and partnerships are among the
greatest sources of our military strength.”23
Accordingly, the JAG Corps contributes to maintaining and expanding the
Army’s network of allies and partners through the interrelated concepts
of security cooperation and legal interoperability.24
With exchanges being one of the JAG Corps’s five legal interoperability
lines of effort (LOEs),25
legal exchange officers constitute a critical component of the JAG
Corps’s contribution to multinational interoperability.
Members of the 3rd United Kingdom Legal Branch (wearing 1st Cavalry
Division baseball hats) pose with members of the 1st Cavalry Division
Office of the Staff Judge Advocate after Exercise WARFIGHTER 23.4 at
Fort Cavazos, Texas. (Photo courtesy of author)
The JAG Corps defines legal interoperability as “[t]he achievement of
shared understanding of respective authorities, permissions,
restrictions, obligations, and interpretations of international and
domestic law and policy that enables the Combined Force to act together
lawfully, coherently, effectively, and efficiently, to achieve tactical,
operational, and strategic objectives.”26
Practically, this means that “[w]e must be able to successfully support
the integration of allied and partner capabilities into a single,
lawfully-conducted, unified operation across each and every warfighting
function.”27
With ASCCs responsible for MPEP programs within their theaters, the
ASCCs’ Offices of the Staff Judge Advocate ensure that legal exchange
officers’ security cooperation and legal interoperability activities
align with their theater’s LOEs. For example, the U.S. Army Europe and
Africa (USAREUR-AF) Office of the Judge Advocate (OJA) nests its legal
exchange officers’ activities within USAREUR-AF’s LOEs. One of those
LOEs is to increase the scale, capability, and interoperability of
allies and partners through activities such as multinational exercises,
multinational training and education, and senior leader
engagements.28
These laws, policies, and procedures result in one of the most
impactful, challenging, interesting, and rewarding jobs that the JAG
Corps has to offer. By way of illustration, MPEP Position UK-69
establishes an exchange of national security law attorneys between 3rd
(U.K.) Division, the U.K.’s warfighting division, and III Armored
Corps.29
The corresponding position descriptions for the U.S. and British lawyers
focus on participation in partner country exercises and enhancing legal
interoperability through working-level defense engagement.30
At the individual level, the judge advocate (JA) exchange officer
principally works for the British Army. An MPEP officer should not be
confused with a liaison officer. The ALS only has 109 lawyers,31
but they exchange one British attorney to utilize a U.S. Army JA in
their premier warfighting division. As such, the JA must pull their
weight in the day-to-day workload expected of a British Army lawyer.
This includes deploying with British Army division and brigade
headquarters on exercises, advising commanders on British military
disciplinary and administrative law, attending and leading unit
training, attending routine divisional staff meetings, maintaining
marksmanship on an assigned SA-80 assault rifle (comparable to the M4
carbine), participating in unit physical fitness sessions and British
Army physical fitness tests, and all the other tasks inherent with being
part of a British divisional staff officer and British Army soldier.
Being a JA legal exchange officer, however, involves more than being a
legal advisor for a foreign military. Interoperability has three
essential elements—technical, procedural, and human.32
Fundamentally, the human domain of interoperability involves cultivating
lasting personal and professional relationships. Shared hardship from
field exercises, arduous professional military education, and strenuous
physical training create enduring trust and confidence within a team.
Sharing a proverbial and literal foxhole inherently brings people
together. I spent approximately a quarter of my two-year assignment on
various field exercises, often living in crew shelters and Warrior
armored vehicles with British soldiers of all ranks and backgrounds. I
attended the British Army Winter Mountain Foundations Course, climbing
the frigid Scottish Highlands with fellow members of the 3rd (U.K.)
Division staff. And, I sweated alongside the division staff during
grueling physical fitness sessions. In doing so, I developed lifelong
friendships based on respect, trust, and confidence.
In an era of heightened geopolitical competition between major powers,
adversary exploitation of rapidly evolving domains and technologies, and
instability from transboundary challenges, unity of effort between
allies and partners has never been so complex or important for U.S.
national security interests.
Moreover, maintaining the type of enduring relationships envisioned by
the MPEP involves more than having a shared military experience. The MOU
that governs the U.S.-U.K. program contains candidate selection criteria
aimed at rooting military families in their host nation.33
As such, my family attended British schools, participated in British
sports groups, had British neighbors, and attended British Army family
events. In doing so, my entire JAG Corps family developed roots in the
U.K. that will persist long after my tour.
Beyond these aims, a legal exchange officer must leverage their
connection with the ASCC, and U.S. Army writ large, to create
opportunities that enhance the procedural and human domains of
interoperability between organizations. The officer should establish
opportunities for combined training between the United States and allied
nations, leveraging relationships to optimize those opportunities for
increased interoperability. For example, I helped generate short-term
exchanges where JAs accompanied ALS officers on British Army warfighting
exercises, and vice versa. In one instance, I worked with the Joint
Readiness Training Center JA observer coach/trainer and a rotational
brigade JA to embed an ALS officer into the U.S. brigade legal section
during a training rotation at Fort Johnson, Louisiana. Similarly, I
worked with the USAREUR-AF OJA and the 7th Mission Support Command to
embed a Reserve JA with an ALS officer during a British armored brigade
combat team’s warfighting exercise at Salisbury Plains Training Area,
England.
These short-term exchanges build a wider bench of JAG Corps and ALS
officers with multinational expertise. The opportunities provide
first-hand insight into their ally’s capabilities. They enable an
understanding of how an ally provides legal support to operations.
Finally, they widen both armies’ networks of multinational lawyers for
future operations and exercises. Legal exchange officers are uniquely
situated to identify and create these opportunities and See them
through to completion.
Likewise, with one foot in both armies, an MPEP officer is uniquely
situated to unite key leaders and subject matter experts from allied
nations. For example, I helped bring together Mr. Fred Borch, our
recently retired JAG Corps regimental historian, field grade officers
from USAREUR-AF, and about a quarter of the ALS’s officers, including
the ALS head of operational law, during an ALS-led staff ride in Germany
to study the International Military Tribunal and subsequent Nuremberg
trials occurring immediately after World War II. This event aided JAG
Corps and ALS officers in building personal relationships. It also
provided the ALS officers with unique insight into America’s past
contribution to international tribunals and contemporary lessons learned
from the U.S. experience with the Guantanamo Military Commissions.
Although a small contingent, legal exchange officers significantly
increase legal interoperability with partners and allies at a time when
national security requires transformative cooperation.34
To overcome the most complex and grave threats to rules-based
international order in recent history, like-minded allies and partners
are working collectively to address our shared challenges.35
This strategic goal cannot be accomplished without legal
interoperability, which is the purpose of the modest cohort of legal
exchange officers. The MPEP enables this cohort, thereby providing the
JAG Corps with a vital tool to enhance multinational legal
interoperability in a direct and lasting way. Thus, to our partners and
allies working together for a safer world, the senior JAs at the Office
of The Judge Advocate General and ASCCs who support the MPEP program,
and the U.S., U.K., Australian, and Polish legal exchange officers of
past, present, and future—THANK YOU, CHEERS, TA, and
dzięki!
TAL
LTC Chatelain is the Deputy Chief of Administrative Law for the
Office of the Staff Judge Advocate, U.S. Army Pacific, at Fort
Shafter, Hawaii. He previously served as the U.S. Legal Exchange
Officer to the 3rd (UK) Division at Bulford Camp, United
Kingdom.
Notes
1. “Gen” is British Army slang for “trustworthy information.” However,
“gen” has varying degrees of trustworthiness. “Scoff House Gen” has
the lowest degree of trustworthiness. “Scoff house” is slang for
“dining facility.” Telling incorrect “scoff house gen” does not
result in adverse social consequences except for mild public
ridicule. “Eyebrows gen” assures a higher level of trustworthiness.
If the “eyebrows gen” turns out to be incorrect (also known as “duff
gen”), the person telling the “duff gen” must shave off his or her
eyebrows. “Robo gen” assures an even higher degree of
trustworthiness, such that a person telling “robo gen” must shave
his or her head to look like Robocop without a helmet. The British
Army has other, less common adaptations of “gen,” which vary based
on unit. If the inaccurate or untruthful individual fails to perform
the consequence related to the appropriate level of “gen,”
significant social implications ensue. Although the author did not
suffer any consequences from providing “duff gen,” these assertions
are nevertheless based on the author’s recent professional
experience as an exchange officer with the British Army as part of
the Military Personnel Exchange Program from July 2022-July 2024
[hereinafter Professional Experiences].
2. JALS Strength Report, 2024 Worldwide Continuing Legal Education,
at slide 3 (Sept. 2024) (unpublished PowerPoint presentation) (on
file with author).
3. The JAG Corps has an O-5 stationed with the British Army
Headquarters, an O-4 stationed with 3rd (U.K.) Division, an O-4
stationed with the Polish Armed Forces General Command, and an
O-3(P) stationed with 1st (Australian) Division. The position with
the 1st (Australian) Division is not reciprocal. Additionally, the
Bundeswehr has assigned a non-reciprocal military legal advisor to
The Center for Law and Military Operations. Professional
Experiences, supra note 1.
4. See History of the U.S.-U.K. Special Relationship and U.S. Policy, U.S. Embassy & Consulates in the U.K., https://uk.usembassy.gov/our-relationship/policy-history
(last visited Jan. 15, 2025).
(last visited Jan. 15, 2025).
5. U.S. Dep’t of Def., National Defense Strategy of the United States
of America sec. IV (2022) [hereinafter NDS]; See also Secretary Hegseth’s Message to the Force, U.S. Dep’t of Def.
(Jan. 25, 2025),
https://www.defense.gov/News/Releases/Release/Article/4040940/secretary-hegseths-message-to-the-force.
6. NDS, supra note 5, sec. II.
7. U.S. Dep’t of Army, Reg. 614-10, Army Military Personnel Exchange
Program with Military Services of Other Nations para. 1-6 (14 July 2011) [hereinafter AR 614-10].
8. 10 U.S.C. § 311; See U.S. Def. Sec. Coop. Univ., Handbook, Security Cooperation Programs 30 (2021).
9. U.S. Dep’t of Def., Dir. 5230.20, Visits and Assignments of Foreign Nationals (22 June 2005).
10. See AR 614-10, supra note 7.
11. Id. para. 1-5(b).
12. Id. para. 5(c).
13. Id. para. 5(d).
14. Id. para. 1-4(b).
15. Id. para. 1-9.
16. Id.
paras. 1-4(b)(2), 2-1, 2-2(7)(c) (the DCS, G-3/5/7 also obtains
concurrence from the Office of the Secretary of Defense Policy
before finalizing or altering programs).
17. Id. para. 3-2.
18. Id.; see also
Memorandum from James Hennessey Jr. & Timothy Thompson, subject:
Memorandum of Understanding Between the Government of the United
States and the Government of the United Kingdom of Great Britain and
Northern Ireland on the Reciprocal Exchange of Army Personnel, sec.
IV (17 Feb. 1988) [hereinafter U.S.-U.K. MOU].
19. AR 614-10, supra note 7, para. 3-3.
20. Professional Experiences, supra note 1.
21. Id. paras. 2-2(f), 5-3.
22. Id. para. 1-4(g).
23. Off. of The Judge Advoc. Gen., The Strategy of the Judge Advocate General’s Corps 2022 [hereinafter JAGC Strategy].
24. Id.
25. Lieutenant Colonel Andrew Farquhar & Lieutenant Colonel
Christopher T. Franca, U.S. Army JAG Corps & British Army Legal Services Exchange
Officer Working Group, at slide 7 (May 2022) (unpublished PowerPoint
presentation) (on file with author).
26. The Judge Advoc. Gen.’s Legal Ctr. & Sch., U.S. Army, Best
Practices of Multinational Legal Interoperability Smartbook A-3 (2024).
27. Lieutenant Colonel Justin Marchesi, Foundations of Multinational Legal Interoperability, Army Law., no. 5, 2021, at 2, 3.
28. U.S. Army Europe and Africa, USAREUR-AF AOR and Operational
Approach, at slide 2 (May 2023) (unpublished PowerPoint
presentation) (on file with author).
29. See
Memorandum from Deputy Chief of Staff, G-3/5/7, subject: Execution
Approval for a Reciprocal Military Personnel Exchange Program
Position with the United Kingdom (U.K.-69) (June 8, 2020).
30. See
Position Description, U.K.-69, Deputy Chief of Staff, G-3/5/7,
subject: For U.S. Army Participant with the British Army; Position
Description, U.K.-69, Deputy Chief of Staff, G-3/5/7, subject:
Position Description for British Army Participation with the U.S.
Army.
31. E-mail from Major Matthew Gosnell to author (Aug. 23, 2023) (on
file with author).
32. U.S. Dep’t of Army, Reg. 34-1, Interoperability para. 1-8(c) (9 Apr. 2020).
33. U.S.-U.K. MOU, supra note 18, sec. 4(a)(v).
34. The White House, National Security Strategy 16 (Oct. 2022).
35. NDS, supra note 5, at 14.