Small Wars Journal

Rules of Engagement: Pro Bono ex Militari

Tue, 11/09/2021 - 2:55am

Rules of Engagement: Pro Bono ex Militari


By Ian Kippen



Rules of engagement (ROE) are the embarrassing uncle at a family party. He is engaged in polite conversation but spends most of the time in the corner being denied top-ups on the drinks and someone, normally the legal advisor in the family, stays sober to drive him home at the earliest opportunity. The operational family is obliged to invite him to the party, but everyone scrupulously avoids conversation and looks forward to his departure.

The best summing up of the need to pay due care and attention to ROE comes from Margaret Thatcher in her memoirs, The Downing Street Years:

The rules of engagement are the means by which the politicians authorise the framework within which the military can be left to make the operational decisions.  They have to satisfy the objectives for which a particular military operation is undertaken.  They must also give the man on the spot reasonable freedom to react as is required and to make his decisions knowing that they will be supported by the politicians. So, the rules have to be clear and cover all potential eventualities.[1]


The purpose of this paper is not to enter into a discussion on the legal aspects of ROE, nor its relation to International Humanitarian Law or the Law of Armed Conflict (LOAC).  The sole purpose is to provide a fillip for commanders, staff, and exercise designers to take ROE more seriously. This paper will look at three key aspects of ROE:  firstly, the broader aspects on getting ROE right; secondly, ROE as giving the authority to conduct military operations; and finally, the development of ROE.

The incentive for this paper comes from two deep frustrations experienced as a NATO operations planner. The first is the refusal of operations staff to put any real effort into the development of ROE: whilst reviewing an unexpectedly familiar exercise Operations Plan (OPLAN) ROE Annex for an exercise, it was cross-checked to find that the ROE had been cut and pasted from the last exercise, which was a completely different scenario and wholly inappropriate, lacking in any original thought.[2] 

The second was that on exercises, the ROE role would be constantly palmed off to the Legal Advisor (LEGAD). You may be lucky and your LEGAD is also an expert in Joint fires, and Special Operations; however, we would doubt that such a savant would be available to the average NATO planner. Commanders and their staff have evaded their responsibilities, leaving their LEGADs to fend for themselves in drafting ROE, where they may have neither expertise nor experience.

Getting ROE Right

ROE is approved by the highest authority and purposefully limit the employment of military force in achieving political objectives. They provide authorisation for and/or limits on, among other things, the use of force, the positioning and posturing of forces, and the employment of certain specific capabilities.[3]  ROE are an essential element of both command and control; ever since the Battle of Megiddo in the 15th century BC,[4] military commanders have placed both restraints and constraints on their forces’ application of combat power, in the understanding that unrestrained, undisciplined and uncoordinated military force generally leads to disastrous results at all levels of command.[5]  However, in future major conflict, commanders may find themselves beyond the immediate control of the higher echelons, as their forebears found when instructions were conveyed by ship, riders, runners and pigeons.

Taking the most serious threat to NATO and the raison d’être for its existence, conflict against the classic peer adversary, Russia, will mean getting our ROE right in our advance planning.[6]  Emphasis is placed on the current consensus that Russia is a peer adversary because, according to a RAND Corporation research paper, Russia has vastly improved readiness and the ability to move forces quickly, combined with the density of anti-access/area denial (A2/AD) capabilities, providing a much greater capability to project force.[7]   Russia is not shy when it comes to demonstrating such capabilities, as seen as recently as April 2021 with manoeuvres to the east of Ukraine and Crimea involving 100,000 troops, 40 warships and multiple aircraft.

What are the chances that NATO will be surprised? Maskirovka (disguise) is still very much ensconced in the Russian military lexicon.  Even if NATO has enough warning time to deploy its high readiness forces to a conflict zone, there is every chance that the electro-magnetic spectrum will be highly contested, and our forces would not be able to communicate, certainly in the first few days. Between 2014 and early 2015, Russia’s use of layered joint fires and large-scale electronic jamming rendered Ukraine’s armed forces impotent.[8]  Commanders will be left with no choice but to think for themselves and fully exercise mission command.[9]  It is not just a case of having a good, well understood, plan; they will need assurance that their military actions are authorised, if they are to be proactive and reduce their vulnerability.  Commanders should certainly not have to rely on the catch-all of self-defence.[10]  Fully understanding the military actions available, which are authorised by ROE, becomes a key tool for mission command. This also strengthens the call for commanders to be fully involved in the development of ROE and discussions on challenges such as cyber-attacks, which complicate traditional notions of ROE. This will be discussed later.

It is common sense that ROE need to be a closely guarded secret; should your adversary have access to your ROE, they can reveal your weaknesses and be used against you. Given the apparent cyber skills of our potential adversaries, chances of keeping the ROE Annex of a plan secret are quite slim. A simple internet search for ROE revealed a great deal of examples, including NATO’s ROE policy document, MC362. Getting the ROE right, with the full comprehension of commanders and operators, becomes more critical.

It is also highly likely that our forces will be multinational. Internationally approved ROE for an operation provides common ground for the use of force, ensuring unity of effort and unity of response by a force comprising units from different nations, each with its own interpretation of international law.[11]  

As commanders take ownership of the ROE, so too must their staff understand what they cannot do and, given the likelihood of early denial of service, what they can and are authorised to do.

The Authority to Conduct Military Operations

An OPLAN has three main purposes: to deploy, employ and sustain the force.[12]  It is the ROE that give the authority to employ the force, and that authority comes from the top, our political masters. But political direction, especially given a nation state’s need to have significance on the world stage, is not enough: a state, or alliance of states’ engagement in conflict requires legitimacy, which is underpinned by legality. Since the end of the Second World War, nations have endeavoured to globalise the response to conflict by setting legal standards for major international issues, and to guide states' behaviour toward those standards. This global process is also characterised by the notion of legitimacy and multilateralism, as exemplified by the efforts made to gain United Nations Security Council authorisation for the use of force.[13]  In following these standards in the interest of legitimacy, nations must provide a clear legal justification and embed clear legal authority in the ROE that will control the use of force, ensuring that those ROE cannot authorise force that is not permitted, primarily, by the Law of Armed Conflict.[14]

In NATO, political authority comes from the North Atlantic Council (NAC), diplomats representing the 30 governments of the Alliance; governance is by the consensus of each nation that provides NATO with the legitimacy to act.  The NAC exercises its authority top-down: it gives guidance for planning military operations through the chain of command, strategic military, through to the Operational and then onto tactical commanders. The plan is developed bottom-up, from the tactical level, the level that will be employed in those operations. It is also at this level, and this is where I diverge from several writers on the topic who see the writing of ROE as a purely strategic level responsibility, that ROE is initially developed; this will be discussed in more detail below. With Political approval of the final OPLAN, which contains the formal ROE request, and the issue of the ROE Authorisation message, commanders are authorised to conduct the operation.[15]

However, nothing is that simple. ROE is a tool for controlling the military force and some nations may place restrictions or caveats[16] against ROE, which will be explicit in the ROE Authorisation message. As operations planners, we would hope to have had notification of restrictions and caveats before the final submission of the OPLAN to avoid radical changes at the eleventh hour, ensuring ROE are clearly understood and implications of the restrictions and caveats to our actions.  For many of our operators, restrictions and caveats could come as a jaw-dropping surprise, as it would never happen on an exercise. Restrictions and caveats, as many who have experienced operations know, is a fact of life. Again, getting our staff to take a full role in ROE development would at least make the adjustments needed and further passage of orders more coherent.

Developing ROE

There is no intention of going into detail on NATO’s operations planning process; a simple internet search will give you plenty of bedtime reading.[17]  Instead, we can home in on the key aspects of ROE development, starting with the strategic military guidance that is further developed at the operational level for detailed planning at the tactical level, and it is at the tactical level that the military actions required to achieve the objectives are formulated.  A key tool for planners is the operational design, which will depict how the military actions will create the effects that will change conditions from undesirable to desirable, the Decisive Conditions. [18]  

The operational design is normally portrayed as a graphic, laying out the commander’s vision for the operation. Figure 1 is a simplified Operational Design: for each given objective, shown as a hexagonal on the right, there is a logical Line of Operation (LOO) that will sequence activity in achieving the objective.  Along the LOO, we find several decisive conditions (DC) represented as triangles, which when attained, provide the commander with the advantage.   The strength or weakness of a DC is derived from the relationships between the component parts; to change these relationships to our advantage, we must create effects, and these effects are created through military actions.

Figure 1: the Operational Design with ROE, from author.

In the design at Figure 1, we have a LOO to achieve the objective of assuring freedom of action (FOA) for international organisations; we have identified a DC that will neutralise insurgent FOA and four effects that will change the current state to our advantage. To create the effect of deterring the insurgents, we will engage both kinetically and non-kinetically. We then identify the ROE required to authorise these actions in the employment of military force.

The formulation of these military actions is a cross-staff business and not just those interested in kinetic activity. In the interests of adopting a comprehensive approach, there will be a range of actions that will contribute towards creating the effect we need. The authority to carry out these actions comes from the ROE, and the formulation of the ROE crosses all functional areas.  It is critical that commanders take ownership of the ROE, and, in the interest of rigour, interrogate their staff on the formulation of the ROE.[19]

The higher most military commander approves the strategic level OPLAN and ROE Request, based on the advice of the planning team; the operational design supports our cognition of the plan by providing a clear audit trail between the objectives and military actions, and the ROE required. Before submitting the ROE for political approval, the commander must be confident that the ROE is fit for purpose.

It is highly unlikely that you will see the explicit link between military actions and ROE in a plan. You will certainly have an annex connecting the DCs, Effects and Actions; the ROE will be in a separate annex. Bringing them together is an aspiration and something to be strongly encouraged.  It wouldn’t just make the strategic planner’s job easier, it would assist the nations, who will scrutinise the ROE, in understanding their relevance.  It would also be invaluable in understanding the impact of restrictions and caveats.

Finally, we should also consider the armchair generals. The speed at which activity on operations is relayed to the public by news networks and social media, has dramatically increased public awareness, with consequences for public support for an operation.[20]  There would also be consequences for public support to future operations, especially when commanders and soldiers may have been deemed to have operated outside of the law.  Readers in the UK will be familiar of prosecutions of military personnel following the troubles in Northern Ireland and the wars in Iraq and Afghanistan. More widely publicised was the Brereton Report into war crimes committed by the Australian Defence Force in Afghanistan between 2005 and 2016. The report found evidence of 39 murders of civilians and prisoners by Australian Special Forces, but more alarming were subsequent cover-ups where the LEGADs had been complicit.[21]  In the interests of legitimacy, it is absolutely right that commanders and soldiers who deviate from the actions that are authorised, are punished if found guilty.  Paying proper due care and attention in the development of ROE, along with the commitment and accountability of commanders, may go some way to preventing violations; it would also help in the identification of violations and the prosecution of those responsible, be it commanders or service personnel.

In summary, the development of ROE is a cross staff function, with the LEGAD complying with the job description: an advisor on legal matters. Commanders must take ownership of the ROE throughout the development process. By developing the ROE from the tactical level upwards and understanding the relationship between the employment of the force and the ROE, we will aid our political masters in understanding the concept for the operation, as well as appreciating the impact of restrictions and caveats. And as a critical command and control tool, our forces will be able to survive to fight another day, able to fully exercise mission command knowing that they are authorised and protected by their political masters.


[1] M. Thatcher, The Downing Street Years, 1993, Harper Collins, page 201

[2] See W. H. Parks, “Deadly Force Is Authorized,” US Naval Institute Proceedings, Jan 2001, page 35

[3] Sanremo Handbook on Rules of Engagement, International Institute of Humanitarian Law, 2009, page 1

[4] Broadly accepted as the first recorded battle in history, see H. Goedicke, The Battle of Megiddo, Halgo Inc. 2001

[5] See G. P. Corn, “Developing Rules of Engagement: Operationalizing Law, Policy, and Military Imperatives at the Strategic Level,” in U.S. Military Operations Law, Policy, and Practice, Oxford Scholarship Online, 2015, page 210

[6] Planning is the writing of contingency plans ahead of the need for the plan to be executed

[7] See Boston, Johnson, Beauchamp-Mustafaga, Crane, Assessing the Conventional Force Imbalance in Europe

Implications for Countering Russian Local Superiority, 2018, RAND Corporation, page 2

[8] O. Manea, “The A2/AD Predicament Challenges NATO’s Paradigm of ’Reassurance Through Readiness’”, 2016, in Small Wars Journal,, accessed 4 March 2021

[9] M. I. Handel, Masters of War, 1992, Frank Cass, p57

[10] See Guldahl Cooper, NATO Rules of Engagement, On ROE, Self- Defence, and the Use of Force during Armed Conflict, 2019, in Brill Publishing, International Humanitarian Law Series, Volume 57, page 320

[11] J. F. R. Boddens Hosang, Rules of Engagement and the International Law of Military Operations, 2020, Oxford Monographs in International Humanitarian & Criminal Law, page 21

[12] Comprehensive Operations Planning Directive (COPD) Version 3.0 dated 15 Jan 21, page 3-75

[13] M. Toshiki, Legality, Legitimacy, and Multilateralism, UN Chronicle Volume 48, Issue 2, 2012, page 24

[14] C. Guldahl Cooper, page 2

[15] M.C. 362, NATO Rules of Engagement

[16] Caveat is a warning or proviso of specific stipulations, conditions, or limitations

[17] For example, the first result in my search found a NATO School Oberammergau slide show,

[18] For more on the operational design and decisive conditions, see: “Help the Plan Survive Contact: Write Better Decisive Conditions,” Kippen, Small Wars Journal, 2017

[19] See W. H. Parks, page 37

[20] J. F. R. Boddens Hosang, p38

[21] E. Massingham, in Opinio Juris, 20 Nov 20

About the Author(s)

Ian Kippen is a retired British Army Officer now working as an independent consultant. He has held Staff Officer positions at SHAPE, JFC Brunssum and HQ ARRC as well as the MA position at UN Missions to Sierra Leone and DRC and held a staff position with NTM-A.