“Shield or Glue” Revisited

Multinational Missile Defense Policy Variables


Marxen W. Kyriss, PhD


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A soldier assigned to 2nd Battalion, 1st Air Defense Artillery Regiment, 35th Air Defense Artillery

In 2018, I published a dissertation titled “Shield or Glue? Key Policy Issues Constraining or Enhancing Multinational Collective Ballistic Missile Defense.”1 My original goal was to show which of eleven ballistic missile defense (BMD)-related policy variables would encourage or discourage a nation from joining a coalition or alliance that used BMD as a core capability. Since its inception and nature, BMD comes with a lot of political baggage, and countries view the implications of its use differently. This article aims to summarize that research and conclude with some assessments about changes in my findings due to changes in the world since 2018.

I based this research on my insights as a fourteen-year-core member of the U.S. Strategic Command’s Nimble Titan campaign series of multinational missile defense (MD) policy experimentation (which has since moved to U.S. Space Command with the transfer of the missile defense mission in the 2023 Unified Command Plan). I learned over several two-year campaigns that eleven MD-related policy topics continued to be the main areas that challenged the players the hardest politically, and these became my policy variables. Nimble Titan is a community of twenty-four nations and three multinational organizations from Europe, the Gulf Region, the Indo-Pacific, and North America, and its participants are split between defense and foreign affairs professionals from all these states.2 Approval by the Nimble Titan national leads to conduct my research gave me unprecedented insights into the variety of thinking on these policy variables as they differ between states and regions, and defense and foreign affairs personnel.

During my research, I learned not only which policy variables might encourage or discourage a nation from joining a coalition or alliance using BMD, but I also found that some were only relevant within an operating coalition or alliance. Some, if poorly handled, could lead to a decision by a state to leave a coalition or alliance. I also learned that some variables were drivers of others and hence had interaction effects, that some were weighted more strongly than others, and that this weighting varied by geographic region. This ultimately caused me to change my original analytical model (see figure 1) to something richer and much more complex.


Briefly summarized, my original research model can be read as follows: Given the listed antecedent conditions, using the intervening variables of state types (those states that own BMD, support other states with BMD directly or indirectly, or do not own BMD or support BMD-equipped states), which of these intervening variables (IVs, listed as hypotheses), viewed through the lenses of national, foreign affairs, and defense perspectives, would encourage or discourage a state from joining a coalition or alliance that uses BMD (the dependent variable)?

Using standardized questions related to the policy variables, data was gathered through extensive interviews with defense and foreign affairs personnel from most Nimble Titan states and multinational organizations.

The Policy Variables Explained

I defined BMD-related policy issues as those involving the use, or potential use, of BMD. This includes discussions between national political and military leadership, and between nations involved in collective political-military action. These issues may require national or multinational decisions or agreements. These issues became the eleven policy variables explored, which, in the original model, broke down into three categories of IVs; that is, those that are adversary-centric, those that are internal to a coalition or alliance, and those that are related to third (or external) parties. In the dissertation, I expanded on each variable’s military and political implications, which we, unfortunately, do not have room for in this article.

Adversary-centric IVs. The first two are relational issues between the country that is considering joining a military coalition or alliance that uses BMD and a potential adversary that uses missiles. While relational, they are also perceptual variables, rather than concrete and quantifiable ones, in that they both include the perceived relationship between the joining state and their potential adversary.

Hypothesis 1 (threat perception). The greater the perception of threat from a potential BM-equipped adversary, the more the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. Two assumptions underpin this: (1) the political situation is such that the state considering joining an alliance or coalition feels potentially threatened by the adversary (i.e., the adversary has possible intent) and (2) the state is within range of the adversary’s missiles (i.e., the adversary has existing capability).

Hypothesis 2 (security dilemma). As adversary concerns with friendly coalition/alliance military buildup increase, adversary tensions and pressure on the state not to join increase, and the likelihood of that state joining a multinational military coalition or alliance that uses BMD decreases. A derivative of the classic security dilemma, as John Herz and Robert Jervis laid out, exists for BMD.3 In this view, the acquisition of BMD may make potential adversaries feel insecure in their ability to use their offensive forces to settle a dispute and hence feel the need to further their offensive capabilities to offset the BMD, thus creating an arms race. Assumptions include that (1) the joining state must have an independent means of settling the dispute with the potential adversary from the rest of the coalition or alliance, and (2) there cannot be prior political commitments to the coalition or alliance that can overcome adversary pressure not to join.

Internal coalition-centric IVs. These factors are internal to the coalition and exist between some or all coalition partners.

Hypothesis 3 (contribution requirements). As national military force contribution and commitment requirements for coalition membership are made less restrictive, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. Assumptions include that (1) there will be some price of admission into the coalition wherein the other states will impose some requirement for national contribution of capabilities to collective military operations; (2) these national contributions and/or commitments will guarantee collective defense of the giving state; and (3) these national contributions may or may not have to be in the form of BMD weapon systems but could also be economic or political support, use of territory for basing or overflight, or contribution of other military capabilities that complement BMD, such as air defenses, offensive strike aircraft, intelligence-gathering capabilities, etc.

Hypothesis 4 (loss of autonomy). As the possible loss of national autonomy for military decision-making and command and control of its forces increases, the likelihood of a state joining a multinational military coalition or alliance that uses BMD decreases. Assumptions underlying this include (1) the states wish to maintain national command over their forces within a multinational coalition or alliance military structure, (2) the proposal is that the state must transfer its forces under the command of military leadership from another coalition or alliance state, and (3) there are no preexisting arrangements between the state and the coalition or alliance for transfer of national forces subordinate to the collective military structure.

Hypothesis 5 (structures and authorities). As collective BMD command-and-control (C2) structures and engagement authorities are made more inclusive, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. I assume (1) the coalition will establish a single military C2 structure, (2) coalition military forces will be subordinated to this single C2 structure, and (3) each nation may impose specific limitations or restrictions (e.g., legal, constitutional, or political red lines) on the use of their military forces, which must be taken into consideration by the coalition military leadership.

Hypothesis 6 (information sharing). As multinational information sharing, information disclosure, and shared early warning increase, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. Assumptions include that (1) all coalition states recognize the value and efficiency gained in sharing information with each other; (2) information disclosure processes within the coalition will be streamlined to ensure more rapid exchange of information before and during a potential conflict; and (3) a shared early warning that consists of the real-time provision of warning of adversary missile launches using satellite, ground, and maritime-based sensors will be provided between all members of the coalition. This is done to warn civil defense and military air and MD forces of an inbound attack.

Hypothesis 7 (plan development). As collective defense prioritization, level of protection guidance, and defensive plans development are made more inclusive, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. This assumes that (1) coalition or alliance military planners will take political guidance and centrally develop a BMD defensive plan that prioritizes what gets defended and to what level of protection. Such planning will dictate where BMD forces are placed, what they will defend, for how long, and how many interceptors BMD forces must be prepared to fire per inbound threat ballistic missile; and (2) the coalition national political leaders will collectively approve such prioritization guidance and planning.

Hypothesis 8 (posture decisions). As collective decision-making regarding posturing of forces (including the military need for deployment versus the political need for deterrence and de-escalation) is made more inclusive, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. Assumptions include (1) nations in the coalition or alliance may collectively or independently work on political measures to deescalate the crisis with the ballistic missile-equipped adversary or to deter his attack; (2) some nations in the coalition or alliance may need to deploy forces into the theater to prepare for conflict, while other states may comprise this theater and already have their forces in place; (3) decisions regarding posturing of forces may be made by the coalition or alliance military structure or could be made by member nations independently; and (4) movement of additional forces into the theater from outside will be visible and seen by the potential adversary, which could, in turn, escalate the situation.

Hypothesis 9 (offensive decisions). As collective decision-making regarding the timing of, triggers for, authorities required for, and legitimacy of offensive operations is made more inclusive, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. Assumptions include that (1) BMD forces are inadequate to defend everything, so offensive strikes on the adversary’s ballistic missile forces are likely to be required to compensate for defensive shortfalls; (2) the decision to commence offensive strike operations against the adversary’s missiles may be required prior to the formal commencement of hostilities; (3) coalition nations may have differing views on what provides legitimacy to authorize offensive strike operations (e.g., some states require a United Nations Security Council resolution authorizing the use of force, while others may feel the situation meets the “clear and present danger” criteria for anticipatory self-defense outlined under the Caroline Incident of 1837; and (4) coalition nations may collectively decide when to begin offensive operations or may feel the need to do so unilaterally. Such unilateral decision-making may stress coalition political cohesion.4

External third-party-centric IVs. These factors apply to how the coalition engages with third parties. We define third parties as nations or multinational organizations that are neither a part of the coalition or alliance nor aligned with the potential adversary.

Hypothesis 10 (consultation processes). As collective consultation processes and engagement with third parties (including strategic communication and declaratory policy) are made more inclusive, the likelihood of a state joining a multinational military coalition or alliance using BMD increases. This assumes that (1) a military coalition or alliance’s nations may collectively coordinate external consultations, strategic communications, or declaratory policies prior to external engagement with third parties, or these nations may independently or bilaterally engage without internal coalition consultation; and (2) coalition or alliance states want to coordinate these endeavors to prevent fratricidal or conflicting messaging with third parties or the potential adversary. I define “consultation” as the exchange of views and the conduct of deliberations either among the authorities of the participants or between participants and third parties (including potential adversaries), aiming at harmonizing positions and formulating recommendations on issues of common concern. I define strategic communications as all actions and activities participants conduct to send persuasive messages to various desired audiences, through the most suitable communication channel, at the appropriate time, to contribute to an overarching strategy. Lastly, I define declaratory policy as information transmitted via diplomatic and/or public channels containing and/or describing the intentions or possible actions of the participants in order to influence the behavior of adversaries, neutrals, or potential supporters.

Hypothesis 11 (consequences-of-engagement planning). As collective planning for consequences of engagement (COE) (including civil warning, consequence management, and liability for damages from successful or unsuccessful MD intercepts) increases, the likelihood of a state joining a multinational military coalition or alliance that uses BMD increases. I assume that (1) states will wish to take all prudent precautions possible in advance of a conflict to minimize COE, and (2) that the degree and scope of what defines prudent precautions is open to debate. I define COE as the political-military consequences from all phases of BMD operations that could arise because of an interceptor’s launch (or lack of launch). This includes consequences of intercept plus prelaunch activities (such as consultation, rules of engagement, intelligence about a potential launch, and planning) that could affect policy and possible military response, and the effects from the interceptor owing to an unsuccessful intercept. Consequences of intercept is defined as the physical hazards arising from the intercept of a threat ballistic missile and its effects on the civilian population, critical infrastructure, and military capabilities. Consequence management is defined as those measures taken to protect public health and safety, restore essential government services, and provide emergency relief to governments, businesses, and individuals affected by the consequences of intercept, engagement or that of a chemical, biological, nuclear, and/or high-yield explosive situation.

The Final Model Explained, with Recommendations for Policymakers

I discovered that there were not eleven BMD-related policy variables that might influence whether a nation would join a coalition or alliance that uses BMD. Ultimately, there were two major factors that seemed to do so but which had important linkages to seven other variables in the precoalition-formation stage. Four of the original IVs were seen as actually more significant once a coalition was formed, while five more were subsets of one of these four. Lastly, five of the original IVs, if mishandled, were cause for a state to leave an established coalition (two of which are only subsets of a larger one). These findings were reflected in my final model (see figure 2).


The model is read chronologically from left to right, with the purple box representing the precoalition-formation stage in which my original dependent variable, the decision to join a coalition or alliance that uses BMD, is captured. The middle green box represents an established coalition or alliance that uses BMD, while the dark red box on the right represents the factors that may result in a decision by a state to leave a BMD-using coalition or alliance.

Starting with the decision to join coalition box, the information sharing IV itself is insufficient to cause a state to join, but one element of it, shared intelligence, is a critical piece in developing the threat perception, whether that of an individual state or the collective threat perception of multiple states. Threat perception itself was observed as one of the two major factors in the decision to join. Without a threat, there is no need to establish a short-term military coalition or long-term military alliance. One spinoff of threat perception was the IV security dilemma, which is, in effect, the reaction of the adversary or other third parties to the actions taken by the state or coalition based on their threat perception. Security dilemma was not seen as either causal of joining or even impactful, but most respondents agreed that the reactions of an adversary or major third party like Russia or China must be taken into consideration. Most felt this would generally be done by an established coalition or alliance via political consultation processes to ensure the intent of coalition action was clearly understood by outsiders.

The six IVs in the bottom half of the decision to join coalition box are also related. Most respondents saw the original loss of autonomy IV as really two elements: only loss of (political) autonomy was significant in the decision to join. Loss of (military) autonomy was not discussed but will be discussed shortly. Where the five IVs below it on the model were discussed as impacting the decision to join, it was generally within the context of how each was an element of loss of (political) autonomy. Consultation processes are viewed as the sovereign right of a nation’s political leadership; should the coalition or alliance mandate nonunilateral consultation, many states would see this as a loss of political autonomy. Within structures and authorities, several states mentioned that maintaining political control over their forces would be done by retaining red cards or caveats on their use; if this loss of political control happened, they would not be comfortable joining a coalition. Within plan development, most states felt that if they lost political control over the planning and defense prioritization that would account for territorial or homeland BMD, they would, again, be uncomfortable joining the coalition; this contrasted with theater BMD planning to protect deployed forces, which was seen as a coalition military concern only. Some also mentioned the loss of political control over elements of posture decisions and offensive decisions, both seen as potentially politically and militarily escalatory, as a potential reason to not join, but again, within the context of “loss of (political) autonomy.”

Left Quote

Threat perception was the main, positive driver in coalition joining, while loss of (political) autonomy (or control) was the single significant detractor that would cause a state not to join.

Right Quote

In short, threat perception was the main, positive driver in coalition joining, while loss of (political) autonomy (or control) was the single significant detractor that would cause a state not to join. Both major IVs linked to several IVs in the next phase of the model.

In the central “in established coalition” box are nine related factors that are seen as mainly only relevant between members of an established and active coalition. Threat perception was shown to be the principal driver behind five IVs. Nations felt the threat would dictate contribution requirements; nations would provide forces necessary to address the types of threats perceived. “Posture decisions” would be made based on how the coalition or alliance perceived the intent of the adversary. Again, engaging with the adversary or third parties would be done via consultation processes based on a desire to deescalate or deter perceived hostile intent by the adversary. Military structures and authorities would be established by political leadership to prepare for a perceived threat. Lastly, as a crisis escalated, and adversary preparations for missile use in conflict became perceived, “offensive decisions” could need to be undertaken based on the imminence of the threat.

Loss of (political) autonomy was seen by many as impacting established coalition or alliance cohesion and effectiveness. Political decision-making and consensus was seen as important behind posture decisions, and consultation processes. The establishment of the C2 structures and relevant authorities behind structures and authorities was necessary to direct subordination of national forces under multinational control in loss of (military) autonomy, and a major prerequisite for offensive decisions, which were seen by several as the decision to go to war.

In an established coalition or alliance with a set structures and authorities military C2 structure, loss of (military) autonomy was observed as a necessary element of this C2 structure in which unity of command and unity of effort are cardinal military virtues; after all, someone must be in charge. Information sharing, offensive decisions, and plan development, particularly for the theater BMD mission to protect deployed forces in a military theater, were seen by many as responsibilities of, or functions necessary for, an effective C2 structure. COE planning was generally seen as a to-do list item under plan development, in that MD planning is not complete without factoring in COE considerations. While discussing consultation processes, many respondents cited the necessity to engage with partners and third parties about potential COE and the need for accurate COE data to inform these consultations; I reflect this in the model with COE planning also feeding into consultation processes as a related variable.

Left Quote

The first, most obvious requirement for a coalition is developing a shared common threat perception. This is the necessary and sufficient condition that collective military action requires.

Right Quote

A major, albeit serendipitous, finding was not just what would cause a nation to join, but, perhaps more importantly, what would cause a nation to leave. This led to the rightmost “reasons to leave” the coalition area of the model. I do not show these as linked to IVs within the established coalition box because they are variables that only apply if handled badly.

Unsurprisingly, since loss of (political) autonomy was the largest detractor from joining a coalition, it should be the one cited most as a principal reason to leave. Should a nation feel it has lost its say in political matters, it would be highly motivated to pull out of a coalition. A related element would be if a state had no say in offensive decisions about when and why to initiate offensive operations. If this political decision to go to war were taken from a coalition member, yet that government would be expected to share the consequences, then that nation could find the domestic and international pressure too much to bear. Similarly, if posture decisions were taken away from a state by the collective, then the state would bear responsibility for any escalatory or provocative actions undertaken by the coalition, which could have a similar impact to offensive decisions. I reflect both IVs as subordinate elements of loss of (political) autonomy in the model for these reasons.

Although only mentioned a small number of times, the idea that bad information sharing would be a deal-breaker for some members has some merit, especially in circumstances in which intentionally bad or incomplete information provided would result in loss of life or damage of vital interests by the receiving coalition member. Lastly, in plan development, several states noted that if their vital national interests were not considered when prioritizing territorial or homeland BMD, they would have no good reason to belong to a BMD-using coalition or alliance. This last is an important consideration, especially when there are inadequate defenses to protect the territories of all coalition members. In summary, these five IVs are the ones extant coalition political and military leaders must pay the most attention to prevent member defection.

Recommendations for policymakers. Based on the final model, I divided my recommendations for policymakers into three groups. The first includes those areas that the coalition-builder must do to successfully achieve coalition building. The second are those that a coalition-builder must not do should they wish to build and sustain their collective. The last are those in which the collective political leadership of an established coalition or alliance should do to optimize the success of the multinational BMD mission.

Must-dos. The first, most obvious requirement for a coalition is developing a shared common threat perception. This is the necessary and sufficient condition that collective military action requires. In the case of a BMD-using coalition or alliance, such common threat perception must be based on a common belief in the capability and intent of a missile-armed potential adversary. Simple negotiations to gain consensus on the threat may be inadequate to spur coalition formation. It is necessary for nations wishing to encourage others to join them to overcome political, procedural, or legal hurdles to share credible military intelligence that highlights potential threats common to all. This must include the adversary’s capability and intent vis-à-vis the threatened states to truly garner support. It is not enough just to say the adversary could hurt a potential partner; they must believe they have incentive to try. Thus, per my model, the intelligence element of information sharing leading to common threat perception that motivates partner nations is imperative.

Second, a nation that wishes to create a coalition or alliance must assure prospective partners it will maintain political control over critical decision-making, even if military autonomy and control is subordinated under another nation within the coalition C2 structure. Specific BMD-related decisions must remain within the purview of individual nations acting within a collective decision-making apparatus. Nations must feel they retain the right to unilateral consultation processes despite the benefits of collective political engagement. Within structures and authorities, caveats or red cards must be retained that enable nations to either withhold their national forces from certain unpalatable or illegal (for them) actions or withdraw from the coalition should the situation become politically untenable. Having a say in territorial defense prioritization to ensure critical national assets, population, and infrastructure make the cut within plan development is another major political element; without this right, states may not feel the cost to join and participate is worth the effort. Lastly, having a political say in the nature of and timing or triggers for potentially escalatory posture decisions to deploy and posture offensive and defensive forces, and offensive decisions to initiate use of coalition or alliance offensive strikes, must be guaranteed to encourage membership. Taking these rights away will not only dissuade joining but could encourage defection from the coalition or alliance, due to excessive domestic and international political costs.

Must-not-dos. The natural obverse of the above would be for the coalition-building nations to restrict critical military intelligence via information-sharing mechanisms to prospective partners that would inhibit the development of a common threat perception. Because foreign disclosure processes are complex and convoluted in many nations, the natural inclination, especially in time-critical situations, maybe to try to build common threat perception without adequate shared and agreed intelligence. The risk of this is that it may actually slow down coalition or alliance building while the builders struggle to convince partners to join without adequate rationale. It will also harm international support for the coalition operations, particularly in the form of United Nations Security Council resolutions, which may require the presentation of credible intelligence. Therefore, states should implement expeditious foreign information disclosure processes in peacetime based on presumption of a need to share rather than the preclusive need to know doctrines integral to most national intelligence apparatuses.

Coalitions and alliances are trust-based, so policymakers within an existing and operational collective must protect the sanctity of information sharing to sustain this organization of like-minded states. Beyond intelligence, if nations appear unwilling to share information about friendly forces or capabilities necessary for collective military planning and operations, this may stress coalition or alliance cohesion and possibly result in fragmentation or even defection. At the extreme, providing intentionally bad information, or intentionally restricting or withholding critical information, may lead to bad decision-making by partner nations and possibly even loss of life or destruction of critical property. This may break the trust of these nations should it become known that it was done intentionally and could lead to partner defection from the alliance or coalition. In the worst case, intentional internal deception may increase coalition risk, as a spurned partner defects, taking what it knows of coalition plans and processes, potentially to be shared with outsiders.

A more significant set of must-not-dos entails taking any actions that would be seen as imposing a loss of (political) autonomy on partners or allies, which could inhibit the desire of a state to join or force a coalition partner or ally to defect should they feel they are losing the ability to perform obligatory political oversight. Care must be taken to ensure states do not believe the collective political body is taking away their say in posture decisions or offensive decisions with which they do not agree but for which they are politically answerable either internationally or domestically. Lastly, the coalition or alliance must ensure states retain a say in collective territorial defense prioritization (plan development), and if the collective military leadership is unable to meet an individual nation’s prioritization demands (due to a lack of BMD resources, assessed lack of need, or because there is no agreed threat to them), they must be clear in explaining their reasoning to these nations to ensure they do not feel their concerns are being ignored.

Should-dos. Many of the IVs discussed ended as policies or procedures used mainly within an extant coalition or alliance. Of these, the following may, if observed being done well from the outside, encourage new members, and internally enhance collective cohesion within a BMD-using coalition or alliance.

There is a strong need for coalition or alliance members to develop and present common strategic messaging to adversaries and third parties via well-defined collective external consultation processes; these must not preclude an individual nation’s consultation processes and, in many instances, may be enhanced by them when a partner nation has an existing relationship or engagement mechanism with the adversary or third party. Strategic communication engagement appears to be important, especially when used to preclude a potentially escalatory security dilemma or posture decision situation with a potential adversary through clarifying coalition or alliance intent about the deployment and employment of defensive forces. These also facilitate engagement with third parties to assuage their concerns about COE damages or liability before, during, or after a conflict.

Similarly, a clearly defined set of internal collective political-military consultation processes to gain rapid political decisions through the entire cycle of military planning and operations is also very attractive. Such deliberate, structured processes as demonstrated by NATO demonstrate a serious, committed organization that may appeal to many external nations.

Because nations join coalition or alliances with expectations that they may need to provide forces or supporting capabilities, having clearly defined roles, responsibilities, missions, and authorities for their national contribution requirements is also important. Suppose processes are in place for partners to easily understand what part their forces play within the coalition or alliance mission and military structure. In that case, these processes may help a joining nation see, up front, what its contribution requirements likely could be. This can be doubly important for BMD-equipped nations wishing to join the coalition or alliance; in such cases knowing what or who they may be required to defend can be used to make cost-benefit assessments and garner political support at home for joining.

Lastly, policymakers within a coalition or alliance need to establish clearly defined roles, responsibilities, missions, and authorities for their military C2 structures and authorities. In addition to normal military headquarters structures for land, air, and sea military operations, BMD-using C2 has additional requirements. This C2 structure must include a well-defined and very inclusive multinational chain of command to mitigate concerns about loss of (military) autonomy by including national oversight by senior military personnel within the collective structure. The collective C2 structure must have streamlined information-sharing arrangements to expedite planning and operations, coupled with the national intelligence necessary to do so. Well-understood, doctrinally rigorous territorial BMD and theater BMD plan development processes that allow all partners seats at the prioritization table are imperative in any BMD-using coalition or alliance.

Multinational C2 structures must also include mechanisms, processes, and tools for COE planning to support national and collective defensive force positioning and COE consultations within and outside of the coalition or alliance. Modeling and simulation tools to perform COE analysis may assuage concerns about liability and damage from debris.

Lastly, the C2 structure must include offensive and defensive planners familiar with all adversary and friendly defensive and offensive systems necessary to provide options to coalition or alliance military leadership and to inform political offensive decisions and their subsequent military implementation.

Conclusion: Changes in the World since 2018 and Their Implications

Continuance of experimentation up through the Nimble Titan 2024 campaign continues to highlight the relevance and importance of these policy variables. However, some significant changes in geopolitics, as well as in the views of the global MD community, have occurred since I drafted my BMD-focused dissertation in 2018.

First, the current war between Russia and Ukraine has significantly influenced previous thinking. Prior to that, it was an almost forbidden topic to discuss MD against Russia; the United States has consistently avowed across its Missile Defense Reviews that its homeland BMD systems are neither sized nor structured to offset the large strategic arsenals of Russia or China, while NATO has been seemingly hesitant to consider changes to its MD to address Russian missile threats.5 This has changed with the war in Ukraine. The United States has placed cruise missile defense of its homeland against Russian long-range cruise missiles on the table, and the 2023 NATO Vilnius Summit Communiqué makes clear a change in NATO IAMD policy against Russian air and missile threats to NATO territories.6 The accession of Finland and Sweden to NATO because of the war also provides excellent case studies for the application of the model in this dissertation—and for further exploration in venues such as Nimble Titan.

Second, the Ukraine conflict also highlights something that is of no surprise to MD practitioners—“BMD” is no longer an adequate stand-alone concept. Nations cannot think of BMD as an activity all by itself. It is generally accepted that BMD is part of a broader MD field, which, in turn is a subset of an even broader integrated air and missile defense (IAMD), which defends against an even wider set of threats. The good news is that, had I replaced all instances of “BMD” with “IAMD” throughout my research, I believe my findings would likely still have generally held.

The last area of emerging thought revealed through continued experimentation and driven by real-world lessons from Ukraine is related to adversary operational use of advanced weapons that are more difficult to defend against than ballistic missiles. These include maneuvering hypersonic glide vehicles, uncrewed aircraft systems, advanced cruise missiles, and so on. While Russian use of these systems in Ukraine has been less-than-impressive (in relative terms), the fact that many of these systems are dual-use (e.g., nuclear and conventional) means they cannot be simply overlooked, and other adversaries that possess similar capabilities may use them more effectively. The major implication here is that if you are unable to defend against these threats credibly, you may be driven to offensive action earlier than against more “traditional” threats. This “need” for anticipatory self-defense makes many nations uncomfortable and places stress on coalitions or alliances in which perceived legal offensive thresholds may vary between partner nations. Anticipatory self-defense against missile threats can be achieved through multidomain approaches (both kinetic and nonkinetic), each of which comes with its own set of policy implications.

Because no one nation can shoulder the complex air and missile fight alone today, the need to continue experimentation to understand multinational IAMD policy, planning, interoperability, and legal issues remains. This just highlights the need for wargames such as Nimble Titan to continue and expand our collective understanding with partners and allies. To quote Sir Winston Churchill, “There is only one thing worse than fighting with allies, and that is fighting without them.”7


  1. Marxen Kyriss, “Shield or Glue? Key Policy Issues Constraining or Enhancing Multinational Collective Ballistic Missile Defense” (PhD diss., University of Nebraska at Lincoln, 2018), https://digitalcommons.unl.edu/poliscitheses/48/.
  2. Wikipedia, s.v. “Nimble Titan,” last modified 9 April 2022, 01:30, https://en.wikipedia.org/wiki/Nimble_Titan.
  3. John H. Herz, Political Realism and Political Idealism: A Study in Theories and Realities (Chicago: University of Chicago Press, 1951); Robert Jervis, “Cooperation under the Security Dilemma,” World Politics 30, no. 2 (January 1978): 167–214.
  4. Anthony Clark Arend, “International Law and the Preemptive Use of Military Force,” Washington Quarterly 26, no. 2 (2003): 89–103; Francis Grimal, “Missile Defense Shields: Automated and Anticipatory Self-Defence?,” Journal of Conflict & Security Law 19, no. 2 (2014): 317–39.
  5. “2022 NDS Fact Sheet: 2022 Missile Defense Review,” U.S. Department of Defense, 4 August 2023, https://media.defense.gov/2022/Oct/27/2003103921/-1/-1/1/MISSILE-DEFENSE-REVIEW-MDR-FACTSHEET.PDF.
  6. “Vilnius Summit Communiqué,” NATO, last updated 19 July 2023, https://www.nato.int/cps/en/natohq/official_texts_217320.htm.
  7. Alex Danchev and Daniel Todman, eds., War Diaries, 1939–1945: Field Marshal Lord Alanbrooke (London: Orion, 2001), 680.


Dr. Marxen W. “Mark” Kyriss, U.S. Army, retired, was the first Army strategist assigned to the U.S. Strategic Command (USSTRATCOM) in 2000. After retirement, he served as a Department of the Air Force civilian from 2005 to 2023 in a variety of policy positions, culminating as chief of defense policy in the USSTRATCOM J-5 from 2009 to 2023. He received his PhD from the University of Nebraska at Lincoln in political science for his dissertation on multinational missile defense policy. He currently works as a senior military analyst for the U.S. Space Command’s Joint Functional Component Command for Integrated Missile Defense and remains the Wargame Control Group director for the Nimble Titan wargame.



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