Major Dan Maurer*
This spring, for the second time, President Trump ordered a precision air strike against another nation’s sovereign territory on the ground that it had used unlawful chemical weapons against its own civilian population, warranting a “strong deterrent” message to uphold international laws and norms. He did so without the explicit authorization of Congress, acting only on his executive powers under Article II of the Constitution. Moreover, his action was based on ill-defined and much debated principles of jus cogens norms and the evolving international legal standard that purports to authorize states to intervene in each other’s sovereign territory where such norms are threatened. In short, Trump’s order operated in a legal grey area, both domestically and internationally, creating a novel challenge for military and civilian officers of the executive branch who are both required to execute the president’s lawful orders and sworn to uphold the Constitution and the laws of war.
When President Trump decided to strike Syrian territory this time, the United States, France, and Great Britain each contributed military force. This time, the use of force was met with Russian counter-rhetoric, calling it an “act of aggression” that is “destructive of the entire system of international relations,” because it lacked a United Nations Security Council mandate, was not self-defense under the meaning of the U.N. Charter, and had no support from any other corner of international law of armed conflict. Moreover, whether President Trump had sufficient legal authority under U.S. law to order these strikes is strongly questioned by some while supported by others.
More than the traditional jus ad bellum issues usually argued over, like proper authority, last resort, just cause, success probability, and macro-proportionality, decisions like this one raise another kind of legal and ethical challenge, a special case of tension that intensifies the already complicated challenges of American civil-military relations among presidents, Congress, and senior military officers. When a president orders the use of military force to strike an adversary’s strategic military capabilities with precision attacks, but does so based on “deeply rooted [American] historical practice,” without reliance on traditional domestic and international legal authorities, senior commanders and the president’s principal military advisor must plan for and execute in a zone of twilight unforeseen even by Justice Jackson.
Discussion among strategic level civil-military authorities, especially given the lack of concrete legal guidance, is characterized by what Eliot Cohen famously called an “unequal” dialogue, given that the President, of course, must always decide. Emphasizing the significance of this dialogue between military and civilian decision-makers, Lieutenant General James Dubik, now an academic philosopher, has elevated what Cohen thought of as practical reality into a “Principle of Continuous Dialogue,” which serves as one of his five necessary pillars in a blend of jus ad bellum and jus in bello justification. Or, in a similar context, what a lawyer would understand to be his or her dutiy to communicate with, and act with diligence for, the client.
Knowing that this dialogue between these unequal partners must happen is one thing; knowing what to say is another. What is the content of the dialogue—what questions should senior military agents ask of their senior civilian principals under conditions where jus ad bellum legitimacy is precariously perched? After all, the Department of Defense’s own Law of War Manual, reflecting US Government policy, has regarded the combination of just war principles, obligations under international treaties, and customary international law (most of it) to be binding on our decisions when, where, why, and how to use military force—irrespective of the reason, duration, tempo, scale, or means used. What could or should the senior military advisor do, given both his subordination to civil authority and his intrinsic moral agency, if he receives unsatisfying answers, or no answers at all, to questions about the legitimacy of an operation? This article offers 13 generic questions that should outline the form and content of the dialogue. I do not imagine that they be used as a script for examination of the civilian decision-maker; rather, the answers to probing questions like these should help inform military and other decision-makers of their legal and ethical duties with respect to these sorts of “twilight” engagements. Absent answers to questions of this sort, it would be right to question whether the senior military agents are adequately following their own policies and rules, or communicating with their principal and exercising their implied duty of diligence—whether it be on behalf of the civilian administration or the public they defend.
This article is based on two assumptions about the legal framework in which this dialogue occurs, and which appear unlikely to change. First, I assume that American presidents will continue to exercise their war power muscle with foreign precision strikes absent explicit domestic or international authorization, based on reasons like those proffered by retired general and judge advocate Charlie Dunlap, the Justice Department’s Office of Legal Counsel, and the White House. Further, I assume that Congress will not intercede with any restraining or clarifying legislation. If these assumptions hold true, serious strategic concerns related to the amount of force, the duration of force, and—most importantly—the purpose of force will remain sources of friction in civil-military relationships. This friction potentially undermines the legitimacy of certain operations (and that of the actors involved) in the eyes of both the domestic and international public. In turn, a lack of legitimacy could contribute to the perception that two core legal principles of modern war, rooted in military doctrine, have been violated: that the use of violent force be indispensable (“military necessity”) as the only viable means left (a “last resort”), and be proportional in light of the objective (the universal “good” consequences outweighed the universal “bad” consequences of violent action).
I. Questions Based on Principled Premises
In this Article, I propose a number of questions that might form the substance of the (hopefully) rich and meaningful dialogue that Cohen and Dubik, among others, advocate. I wish to emphasize that these thirteen questions implicate not only jus ad bellum (and some jus in bello) concerns, but also practical and legal considerations touching the Constitution, legislation, history, and political theory. Constitutionally, the President is the commander-in-chief of the armed forces, whether in peacetime, war, or some epoch in-between, and has independent (though not unfettered) discretion in foreign affairs and the use of military force. Congress, too, has war-making powers, even if those powers are inconsistently used and have generally been relegated to budget, oversight, and confirmation hearings. On this front, Congress has a history of general acquiescence to presidents’ unilateral deployments of force when the engagements are expected to be “limited.” The constitutional extent to which military leadership possesses independent decision-making authority (if any), and the legal relationship of military authority to the Executive and Legislative branches and the public is less clear.
This relationship, however, is not completely opaque. The Goldwater-Nichols Act created the office of the Chairman of the Joint Chiefs of Staff (CJCS), who serves as the primary military advisor to the President and Secretary of Defense, is the highest ranking military officer, and is responsible for helping mediate capabilities, resources, and plans among the various Combatant Commands. The commanders of those Combatant Commands, in turn, are directly accountable for operations to the Secretary of Defense and the President. More fundamental than the organization command and control diagram, these military officers swear an oath to “support and defend the Constitution of the United States against all enemies, foreign and domestic . . . bear true faith and allegiance to the same . . . [and to] well and faithfully discharge the duties of the office.” Furthermore, the War Powers Resolution grants the President a modicum of unilateral authority with certain caveats.
Moreover, historical patterns of practice have created some robust and predictable expectations where statutory and constitutional law is silent. For example, senior officers will obey lawful orders, resign under pressure, or accept relief from command without creating a panic of a pending coup d’état.
Similarly, at the senior strategic level, military officers do not, in fact, simply wait for orders and execute snappily without dissent, like well-trained Stormtroopers. Rather, political leaders have always relied on military leaders’ sound judgment based on technical expertise and experience, generating an unequal but continuous dialogue concerning the use of force. From Samuel Huntington, we know there ought to be at least some formal barrier between those responsible politically and those responsible militarily, with a traditionally high amount of discretion afforded to the military experts. From Peter Feaver and others, an instructive way to think about the nature of the civil-military relationship is as that of a principal (civilian political leader) who relies upon specially-selected agents (senior military commanders or members of the Joint Chiefs of Staff) to carry out tasks that are beyond the technical capability or desires of the principal. 
From all of this, we can deduce three basic characteristics of the military-civilian relationship that shape the decision-making dialogue. First, senior strategic military and political leaders are separated—in terms of duty to serve the public—by a marginal difference of degree. Both seek to accomplish, ultimately, the same goal of lawful national security. Second, the relationship is fundamentally one of generalized, political authority over professional, ostensibly apolitical specialization. Finally, the military agent is expected to provide a trinity of services: advice (about how to employ military force), action (employing military force), and ability (advising and acting with a certain competence). These characteristics form the premises for these thirteen questions.
II. Thirteen Questions to Guide the Conversation
Before each question, I will first discuss the compelling concern—sometimes ethical, sometimes factual, sometimes legal, or all three—from which it follows.
1. First, it would be a contradiction in terms if “limited” operations the President may order solely under Article II authority could constitutionally last for an indefinite period. In order to properly judge the kind and tempo of force required, senior military leaders ought to know how long the civilian leadership anticipates the commitment will be. Both the jus ad bellum and jus in bello versions of proportionality are implicated here, for the amount of violence and damage inflicted is a partly a function of how long the thumb presses the trigger, not just what kind ammunition is fired. Therefore, the dialogue should include an answer to the question: What expectation does the President have for the duration of this use of force?
2. As President Trump once said of our forces in Afghanistan, field commanders are often given “total authorization.” Lest we face an egregious MacArthuresque interpretation of that authority, military agents ought to know whether they have independent discretion to escalate the battle where the initially intended results are usually quantifiable. The intended smaller scope of authority in these cases is not a set of handcuffs (especially where there is no constraining domestic authority); indeed, it still may be necessary to intensify and enlarge the scope of engagement as conditions on the ground evolve. But expansion risks exceeding the original scope and the original “just cause.” In other words, it is not enough to conclude that—in jus ad bellum terms—we had a high probability of success, or that we initially had the “right intention.” The question here is who has the authority to make decisions regarding the scope of the engagement. Will the combatant commander, or the relevant subordinate field commander, have independent authority to escalate, reduce, or terminate commitment of military force without prior authorization by, or notification of, the President and Secretary of Defense, collectively known as the National Command Authority?
3. Both the military agent and civilian principal must have a clear notion of where the scope of authority begins and ends. These questions might be considered applications of what Dubik calls the “Principle of Final Decision Authority.” Given the technical acumen and experience residing with senior strategic military agents, civilian political leadership must rely in part on the actions of their experts. Because ultimate accountability, in a democracy, for the state’s use of armed force falls on the backs of civilians, the concern is how long of a leash ought to restrain the expert’s independent judgment. Two related questions, addressing this concern, might be: What military criteria, if any, justify a decision to escalate, and what are the criteria for reducing and terminating the use of force?
4. Next, we ask about justification. Borrowing from criminal law theories of punishment, is the military action intended to be a specific or a general deterrent? Is it incapacitation, meant to disable the adversary’s ability to continue doing what has earned our condemnation? Are the effects of the strike intended to be short term or is the incapacitation to be indefinite? Is the use of force basic retribution or retaliation (lex talionis), or a restoration (“restitution”) of some preferred status quo ante? Or is it more like “rehabilitation”—to alter the adversary’s behavior so that it will not want to engage in that wrong behavior again?
The principle of rational justification—the intent behind the use of force—gives the military planner more context from which to design the kind of force appropriate to the circumstances, just as a judge considers the various theoretical intents of the justice system when choosing to mete out a particular sentence. From the legal point of view, this analysis implicates both jus ad bellum principles of just cause and right intention, but also speaks to the principle of “proportionality”—that the degree of violence used should be proportional to the military objectives sought. At bottom this question reflects the wisdom of the adage “don’t take a butter knife to a gun fight,” and its converse, “don’t drop a bomb when a shovel will do just fine.” Beyond simply identifying a target (e.g., an individual, a weapons or command and control facility, base camp location, or force capability), what is the principle of rational justification for application of this military force?
5. Relatedly, the parties should have a meeting of the minds about what interests are at stake if no military action is taken. As described by President Trump, the second Syria strike was a manifestation of a “vital national interest”: “[t]he purpose of our actions tonight is to establish a strong deterrent against the production, spread and use of chemical weapons . . . [e]stablishing this deterrent is a vital national security interest of the United States.” A vital national interest is something (physical or metaphysical) of extraordinary value to be protected—with violence and sacrifice if necessary; it cannot be one’s own use of the force justifying one’s decision to use that force. Therefore, it would not be sufficient in decision-making conversations to suggest that a military action advances a national interest. We need to know how and which one. Implying the jus ad bellum principle of just cause, the follow-up question ought to be: How does this principle of rational justification support a specific, articulable national interest?
6. But military action is never really one-sided (to paraphrase Clausewitz, it is a polarized wrestling match), nor does it occur in a geopolitical vacuum. This remains true even when we intend our application of force to be swift, localized, and overwhelming. Part and parcel of all military planning is the assessment of the enemy’s “most dangerous” and “most likely” courses of action, to consider how they will perceive our actions and are likely to respond. It is not enough to simply do this military calculation; the National Command Authority should explicitly acknowledge these risks and add to them its own analysis of the diplomatic, economic, and political consequences. While President John F. Kennedy once instructed his Joint Chiefs to be more than mere military tacticians and technical experts, the most appropriate use of this sprawling judgment is when both the agent and principal have this conversation, and the earlier the better. In question form: For any principle of rational justification identified, has the National Command Authority anticipated and weighed the effects of likely adversary responses?
7. Of course, actions and reactions can have a long life-span. For lack of a better phrase, the parties, ostensibly aiming for “limited” and “brief,” would like to avoid “mission creep” or at least sense the areas in which it is likely to spawn. Though in some sense this is merely a practical problem, it nevertheless still implicates concerns over proportionality, right intention, and just cause. In other words, is it possible to forecast plausible scenarios in which our use of force has strayed too far from the original intention and the just cause, and—as a consequence—risks being a disproportionate response? Of those anticipated adversary responses, which of them require (or imply) additional U.S. military presence, force, or other action beyond that which is needed for current proposed operation?
8. Part mission creep-avoidance and part good neighbor-conduct, the President must determine where the agent’s responsibility ends. Unlike an attorney consulting with others in his firm about his client’s case, the military practitioner has no such freedom to maneuver unless granted such freedom by the civilian administration which is ultimately responsible for our foreign relations. A commander should therefore be able to answer: To what extent may the military commander responsible for execution of military operations notify, consult with, or advise ally or partner nation military counterparts?
9. But it is not only with other nations’ military leaders that soldiers may interact. During the American Civil War, Congress regularly called serving officers to testify about battles and campaigns recently fought,  imposing an incalculable cost in time and distraction and forcing opportunities to create rifts (or widen existing ones) between the commander-in-chief and his field generals. Of course, the President’s prerogative to expect that confidential or classified discussions will remain so is balanced against the officer’s oath to support the Constitution and rule of law, in a system where Congress must be informed of national military strategy and resource requirements. Because it is a delicate and often contentious matter of balancing candor (to Congress and the public) against fidelity (to the office of the President), the senior military leadership must know the depth and breadth of its authority to communicate with Congress, case-by-case. Therefore, to what extent may the military commander or CJCS notify, consult with, or advise individual members of Congress, congressional committees or subcommittees about the planning and execution of this operation (before, during, or after it concludes)?
10. Again concerned about the proper balance between candor and confidentiality, communication about the use of force extends beyond Pennsylvania Avenue and Capitol Hill. Does the President want uniformed leaders available to sit before Sunday morning political talk show hosts, or to tweet to the public? Prudence suggests that the military agent and civilian principal have a meeting of the minds about: to what extent may military commander or CJCS notify or communicate with the public about this operation via media?
11. In highly contentious situations like the second Syria strike, or other forms of limited U.S. military intervention, initial claims of legal authority by the Executive may face a strong cross-examination both domestically and internationally. General Dunlap has suggested that, beyond satisfying a vital national interest, President Trump’s strike decision was lawful because: (1) the act was “brief and limited,” (2) Congress has not previously acted to restrict his authority to direct such attacks for such purposes, and (3) the act is a continuation of precedent that has created a “hybrid” norm of international law combining elements of reprisal, jus cogens, and hostis humani generis (when the fact pattern involves the “virtually universally prohibited weapon of mass destruction  used against civilians”).
Unfortunately, and as General Dunlap knows well, that vaulted status of precedent is not meaningfully or universally enforced in international law. Nor does “precedential” mean “sacrosanct.” Neither “brief” nor “limited” are defined legal terms, and are unhelpful to planning where applied retroactively. Finally, Congress’s inaction to date does not necessarily imply acquiescence henceforth (though the Supreme Court does give this fact some weight). The urgency of the moment is often an available justification for expansion of presidential power in the face of congressional passivity. But these justifications are not permanent restraints on congressional confrontation. If General Dunlap’s criteria are to be guideposts for commanders and factors to consider in a legal analysis, the answers to these thirteen questions ought to further refine what it means to be “brief and limited,” whether the act does in fact represent a continuation of good precedent, and whether Congress has constrained or enabled the President’s unilateral discretion and command (or could be expected to), all of which military leaders must be assured to warrant the performance of their duties when the President acts without external legal justification. What diplomatic and/or political-centric efforts will be made to secure non-Article II legal legitimacy for current or future military action?
12. It is an essential task for a military leader when advising his or civilian principal to move the dialogue back to the gritty, painful reality of combat, even where it appears clean and surgical. Merely presuming that the President prefers low risk operations across the board, while surely sensible, is insufficient. Before having military options placed on the table, presidents ought to define their anticipated cost in lives and treasure, both our own and that of the intended target. At least for the second part, this question would help better clarify potential challenges on grounds of jus ad bellum “probability of success” and jus in bello concerns for distinction between combatant and non-combatants, limitation of unnecessary collateral damage (micro-proportionality), and prevention of unnecessary suffering. Therefore, what is the President’s expectation for a) the risk to U.S. forces (in terms of materiel and personnel) and b) the risk of non-combatant collateral damage?
13. A final question once more addresses the scope of the military agent’s responsibility and authority—at what point is she alone expected to publically describe and explain the action? To what extent does the President desire the military itself to describe its own use of force? The answer to this question may have implications for the degree of trust (and therefore confidence) the public is able to sustain in the leadership of its Armed Forces, especially if the timing of that communication leads to inconsistencies between the military’s messages and those of the White House. When will the President expect the military to provide the public and/or Congress an explanation for, and description of, the use of this force—before, during, or after its application?
Does answering thirteen questions seem unreasonable or implausible? Given the stakes involved—to American foreign policy, to legal legitimacy, to public support, to the actual risk of lives and property overseas—I think this is not too much to ask. These questions, however they may be answered, can address three primary concerns inherent in the use of force where jus ad bellum legitimacy is questionable. To loosely borrow a concept from fiscal law, the answers to these questions speak to Purpose, Time, and Amount. What purpose drives the use of this force? How much time do we need to use force to achieve that purpose? What kind and amount of force achieves that purpose in that time? In other words, what makes the engagement “brief and limited?”
III. Consequences: an Articulable Basis for Dissent?
Does not answering some or all of these questions grant the strategic military leader freedom to exercise principled dissent? Or might that inability or reticence even establish the conditions by which a duty to dissent is created? On the one hand, a strategic military leader may think that this inability or reticence is a prima facie signal that the decision to use force is probably unlawful, not just a bad idea. In such a scenario, the question of whether one should continue participating in that dialogue and enabling the political decision to use force is not one of virtuous “principled dissent” at all—it is simply the officer’s duty to not follow an illegal order.
Unfortunately, two facts suggest that such a black and white dilemma is unlikely. First, I hoped to convey that this unequal dialogue (at least in the particular kind of scenario suggested by the second Syrian strike) involves a substantial number of questions, and probably even more derivative questions. In other words, the scope of considerations coupled with the bureaucratic and interpersonal dynamics of the key players make this an exceptionally complex space. Second, I hoped to convey that there is almost certainly no textbook “right” or “wrong” answer to any of the questions. The problem is inherently “wicked.” There is, therefore, a better-than-negligible possibility that a senior officer could conclude the decision is probably lawful, but morally questionable. This is where the issue of “principled dissent” does surface.
Regrettably, the “protected space”—or circumstances—in which that surfacing happens is by no means universally marked. Though he speaks more about the manner in which a senior officer could manifest his or her dissent, Marine Lieutenant Colonel Andrew Milburn controversially suggested that the reason for dissenting involves a kind of proportionality analysis: it is right to disagree, and disobey if ignored, when the order is immoral, where immoral means “that [it] is likely to harm the institution writ large—the Nation, military, and subordinates—in a manner not clearly outweighed by its likely benefits.” But Milburn does not discuss on what grounds that reasoning is supported. The answers to the sort of questions I have offered might be worth examining as those potentially cogent, acceptable, and legally-justifiable grounds for dissent. If they do offer that sort of value, it would significantly reduce the danger that dissent or disobedience (say, through resignation) is publically perceived as a disrespectful slap in the face of civilian control of the military, or some sort of existential threat to democracy based on the military leader’s political preferences or personality biases.
Peter Feaver has argued against the use of resignation as a means for military officers to register dissent with the decisions of their civilian superiors:
Resignation in protest is a public political act of defiance against a sitting commander in chief, and its intended result is to produce a political crisis that paralyzes and perhaps reverses the trajectory of a president. To be fair, such a political crisis would not be tantamount to a coup, but it could be a civil–military clash of considerable consequence.
Feaver’s description would indeed result in a perverse perception of the military’s relationship to civilian authority, but is not an inevitable consequence of resignation. Rather, where the public views the act of resignation as executed on the basis of coherent principles outlined ex ante, it would be more likely to view it favorably. The conscious act of asking and answering these thirteen questions may save not only the senior military leader’s conscience but also the moral legitimacy of the military itself from that leader’s choice as a moral agent to disobey, publically dissent, or resign in protest.
Deeper study is needed, but we might say with reasonable confidence that without answers to these thirteen questions, entering into this zone of twilight should be considered high risk (from both a restraint and legitimacy point of view), regardless of how many allies or partners are along for the ride. Where there is no domestic or international legal authority beyond Article II for a given military action, the senior military officer is caught between a duty to the law (including international law of armed conflict) and following the orders of the commander-in-chief under the essential justification “because I, the President, said so.”
The substantive dialogue in this Q&A permits both civilian and military leaders to read clearly from the same page inside the zone of twilight created by precision military strikes absent explicit legal justification. Indeed, it will help maintain shared expectations and improve the quality of expert planning, the depth of the civilian judgment, and the trust between civilian and military authorities as they design, plan, and execute the strike. Most importantly, though, this dialogue represents the tacit acknowledgement that the legitimacy of a military operation (whether wholly legal, wholly public, or a bit of both) is important enough to worry about, and that its absence yields more questions than answers.
*Dan Maurer is an active duty Army lawyer and Non-Resident Fellow at West Point’s Modern War Institute. As a combat engineer officer, he deployed to Iraq as a platoon leader; later, he was the first judge advocate selected to serve as a Fellow on the Army Chief of Staff’s Strategic Studies Group. His scholarly interests gravitate toward strategic civil-military relationships, and has authored Crisis, Agency, and Law in U.S. Civil-Military Relations (Palgrave MacMillan, 2017), a chapter about the subject in Strategy Strikes Back: How Star Wars Explains Modern Military Conflict (Potomac Books, 2018), and a forthcoming article suggesting some amendments to the Goldwater-Nichols Act in volume 10 of Harvard National Security Journal. Major Maurer has guest lectured at the United States Military Academy and the Royal United Services Institute (RUSI) in London, and has published at Small Wars Journal, Military Review, Lawfare, and in several leading specialty law reviews on criminal procedure and dispute resolution subjects. He has practiced as a military prosecutor, appellate counsel, senior legal counsel to a brigade deployed in Iraq, as the Chief of Military Justice for a large Midwestern installation, and currently serving in Italy as a Chief of Operational Law. These views do not represent the positions of the Army Judge Advocate General’s Corps, the Department of the Army, or Department of Defense.
 Stanley Milgram, Obedience to Authority 8 (2009).
 Eline Gordts & Willa Frej, Trump Orders Strikes On Syria In Retaliation For Chemical Attack, HuffPost (Apr. 13, 2018, 9:04 PM), https://www.huffingtonpost.com/entry/trump-strikes-syria-retaliation-chemical-attack_us_5acc7508e4b07a3485e7e642?guccounter=1.
 See id.
 See Charlie Dunlap, Do the Syria strikes herald a new norm of international law? Lawfire (Apr. 14, 2018), https://sites.duke.edu/lawfire/2018/04/14/do-the-syria-strikes-herald-a-new-norm-of-international-law/.
 Compare, e.g., Jack Goldsmith & Oona Hathaway, Bad Legal Arguments for the Syria Airstrikes, Lawfare (Apr. 14, 2018, 1:54 PM), https://www.lawfareblog.com/bad-legal-arguments-syria-airstrikes with Charlie Dunlap, Yes, There Are Plausible Legal Rationales for the Syria Strikes, Lawfare (Apr. 14, 2018, 9:00 AM), https://www.lawfareblog.com/yes-there-are-plausible-legal-rationales-syria-strikes.
 Apr. 2018 Airstrikes Against Syrian Chemical-Weapons Facilities, 2018 WL 2760027 (O.L.C. May. 31, 2018), at 1, https://www.justice.gov/olc/opinion/file/1067551/download.
 See Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579, 637 (1952) (Jackson, J., concurring).
 See Eliot A. Cohen, Supreme Command: Soldiers, Statesmen, and Leadership in Wartime 12 (2002); see also generally Eliot A. Cohen, The Unequal Dialogue: The Theory and Reality of Civil-Military Relations and the Use of Force, in Soldiers and Civilians: The Civil-Military Gap and American National Security 429 (Peter D. Feaver, Richard H. Kohn eds., 2001).
 See James M. Dubik, Just War Reconsidered: Strategy, Ethics, and Theory 138 (2016).
 See U.S. Dep’t of Defense, Office of the General Counsel, Law of War Manual 8–15 (2016), https://www.defense.gov/Portals/1/Documents/pubs/DoD%20Law%20of%20War%20Manual%20-%20June%202015%20Updated%20Dec%202016.pdf?ver=2016-12-13-172036-190.
 Dunlap, supra note 4.
 Steven Engel, Dep’t of Justice, Office of Legal Counsel, Memorandum Opinion on April 2018 Airstrikes Against Syrian Chemical-Weapons Facilities (2018), https://www.justice.gov/olc/opinion/file/1067551/download.
 See Law of War Manual, supra note 11, at 41–42 (discussing jus ad bellum principles of “necessity” and “proportionality”).
 See U.S. Const. art. II. For scholarship illustrative of the breadth of disagreement over the scope of the President’s powers, compare Lawrence Lessig & Cass Sunstein, The President and the Administration, 94 Colum. L. Rev. 1, 1 (1994) (arguing that the “unitary executive” theory of presidential power is “just plain myth”) with Steven G. Calabresi & Saikrishna B. Prakash, The President’s Power to Execute the Laws, 104 Yale L. J. 541, 550 (1994) (countering that “the originalist textual and historical arguments for the unitary Executive, taken together, firmly establish the theory”).
 See U.S. Const. art. I; see also Youngstown Sheet & Tube Co., 343 U.S. at 610 (Frankfurter, J., concurring) (“The powers of the President are not as particularized as those of Congress.”).
 See 10 U.S.C. §§ 152, 153.
 See 50 U.S.C. § 1541.
 See, e.g., Eun Kyung Kim, McChrystal on resignation: ‘I wanted to stay in the job’, Today (Oct. 14, 2016), https://www.today.com/news/mcchrystal-resignation-i-wanted-stay-job-1B7854301.
 See Matthew Moten, Presidents & Their Generals: An American History of Command in War 227–70 (2014).
 See Samuel P. Huntington, The Soldier and the State: The Theory and Politics of Civil-Military Relations 83–85 (1957); see also Cohen, Supreme Command, supra note 9, at 7–8.
 See generally Peter D. Feaver, Armed Servants: Agency, Oversight, and Civil-Military Relations (2003); Daniel Maurer, Crisis, Agency, and Law in US Civil-Military Relations (2017). For a cogent criticism of the micro-economic agency modeling of these relationships, see Dubik, supra note 10, at 61–69.
 See William Manchester, American Caesar 758–59 (1978); H.W. Brands, The General vs. The President: MacArthur and Truman at the Brink of Nuclear War 335, 348 (2016).
 See Dan Maurer, Meeting of the Minds: How Presidents and Generals Stake out Their Territory, Lawfare (May 18, 2017), https://www.lawfareblog.com/meeting-minds-how-presidents-and-generals-stake-out-their-territory.
 See Dubik, supra note 10, at 149–50.
 Gordts & Frej, supra note 2 (embedded video).
 Memorandum from John F. Kennedy, President of the United States, to Lyman Louis Lemnitzer, Chairman, Joint Chiefs of Staff, on Relations of the Joint Chiefs of Staff to the President in Cold War Operations (National Security Action Memorandum 55) (June 28, 1961), https://www.jfklibrary.org/Asset-Viewer/sjtthyMxu06GMct7OymAvw.aspx.
 See generally, e.g., U. S. Congress, Report of the Joint Committee on the Conduct of the War (1865), https://archive.org/details/reportofjointcomm01unit.
 See Doris Kearns Goodwin, Team of Rivals: The Political Genius of Abraham Lincoln 425–26 (2006).
 See 10 U.S.C. § 153(b)(3).
 See Dames & Moore v. Regan, 453 U.S. 654, 686 (1981) (“Past practice does not, by itself, create power, but ‘long-continued practice, known and acquiesced in by Congress, would raise a presumption that the [action] had been [taken] in pursuance of its consent.’”) (quoting United States v. Midwest Oil, 236 U.S. 459, 474 (1915)).
 See Peter M. Shane & Harold H. Bruff, Separation of Powers Law: Cases And Materials 830 (2d ed., 2005).
 See generally U. S. Gov’t Accountability Off., Off. of Legal Couns., Principles of Fed. Appropriations L. 2-1–2-92 (4th ed., 2016).
 For background on the concept of principled dissent, see generally Andrew R. Milburn, Breaking Ranks: Dissent and the Military Professional, 59 Joint Forces Q. 101 (2010), http://www.dtic.mil/dtic/tr/fulltext/u2/a536591.pdf.
 See T.C. Greenwood & T.X. Hammes, War planning for wicked problems, Armed Forces J. (2009), http://armedforcesjournal.com/war-planning-for-wicked-problems/ (“There is increasing awareness within the Defense Department that wars are interactively complex or ‘wicked’ problems.”).
 See Don M. Snider, Strategic Insights: Should General Dempsey Resign? Army Professionals and the Moral Space for Military Dissent, Strategic Stud. Inst. (Oct. 21, 2014), https://ssi.armywarcollege.edu/index.cfm/articles/Should-General-Dempsey-Resign/2014/10/21 (But [the legitimate space of military dissent] is a narrow [one], indeed. Knowing with certitude which acts fall in this narrow space will never be easy.”).
 Milburn, supra note 35.
 Peter D. Feaver, Resignation in Protest? A Cure Worse Than Most Diseases, 43 Armed Forces & Soc. 29, 32–33 (2016).