What Should We Hope For? In Search of Reasonable Definitions of Success

Abstract

The criterion of “reasonable likelihood of success” clearly depends on a reasonable definition of success. This article suggests three such definitions and discusses these in light of the great uncertainty that accompanies any use of this forward-looking just war criterion. The importance of thorough understanding and knowledge, both military and cultural, in order for the application of the reasonable likelihood criterion to be meaningful is also discussed.

Keywords:

• success
• reasonable hope
• reasonable likelihood
• just war
• empathy

When we speak of “reasonable hope of success” or “reasonable likelihood of success” within just war discourse, it is crucial that we define success. There are, after all, myriad ways of succeeding. What will come across as successful to some will be labeled defeat by others. Sometimes, definitions will even be adjusted along the way in order to make it possible to claim success in the wake of seeming failure.¹

In addition to discussing the uncertainties inherent in the reasonable likelihood of success criterion, I will, in the following, suggest three possible interpretations of success in a justified war and see how each of them throws a different light on the permissibility of resorting to armed force.

The first is success in achieving, without unreasonable costs, a full and tidy victory over one’s enemy, reaching one’s stated aim(s) for resorting to armed force.

The second is the more limited one of succeeding in concrete war aims, such as winning back territory, destroying infrastructure, or slowing an invasion force, generally laying the groundwork for a longer-term likelihood of full success without in any way guaranteeing it.

The third is the psychological act of succeeding in convincing one’s own population or one’s own side—including one’s allies—that one is willing and able to fight, that one believes in one’s cause, and that one is not giving up. Even a fight against hopeless odds can be a success on these terms.

In all three cases, I assume, for the sake of argument, that the side we are analyzing respects the law of armed conflict, including but not limited to the ad bellum just war criteria of just cause, right intention, and competent authority, as well as the in bello criteria of discrimination and proportionality. In other words, what the imagined protagonist of this article is contemplating, as they mull their chances of success, is the execution of a defensive or otherwise justified war with legitimate means ordered by a competent, legitimate authority.

Uncertainty

The main challenge of the reasonable likelihood of success and other “prudential” just war criteria is their chronologically forward-looking character.² They ask us, in short, to make judgements based on what has not yet happened and what we cannot know.

Arguably, we often overestimate our ability to predict success. World War I is a classic example, with optimistic beliefs in a limited war that would be “over by Christmas” characterizing initial reactions to the onset of armed conflict in Europe’s midst (Imperial War Museums n.d.). George W. Bush’s famous—some would say infamous—statement “Mission Accomplished,” formulated two months after the intervention in Iraq in 2003, stands as another instance of underestimating the difficulties of defining and achieving success (Koteskey 2023). Indeed, foreseeing the consequences of one’s resort to arms before the full onset of fighting occurs is notoriously difficult.³

Nonetheless, it is possible to calculate probabilities based on resources, willingness to fight, and historical experience. Based on available knowledge of Saddam Hussein’s war machine and the morale among Iraqi troops, and factoring in one’s own great strength, the international coalition that committed forces in the Gulf War of 1991, led by the United States, came in their calculations close to the ideal of great probability of full success, defined as the expulsion of Iraqi troops from Kuwaiti soil and a full restoration of Kuwait’s sovereignty. Their campaign was assisted by a mandate from the United Nations, which ensured widespread (albeit far from unanimous) international support.⁴

The situation 12 years later was different. The war aims of what is often called the Second Gulf War were significantly harder to achieve, since a change of regime in Baghdad was, in practice, deemed necessary to achieve one’s stated goal: control of Iraq’s weapons programs, and a full stop to any development of weapons of mass destruction. Compounding the difficulty was the lack of a strong international coalition with a clearly stated mandate from the United Nations, as well as faulty intelligence.

Full or Limited Victory?

In line with the foregoing observations, we can surmise that the following combination will increase one's likelihood of success: (a) Plentiful military resources, both technological and in terms of personnel; (b) political and moral backing from one’s allies and the international community through the United Nations as much as possible; (c) access to reliable and plentiful information; and (d) a strongly argued and morally sound cause for resorting to force in the first place. In the ideal or “best-case” scenario, this leads us to the first category above, in which the costs of committing forces to fight a war are legitimized in large part by the fact that the likelihood of success at a reasonable cost is so significant.

In other cases, however, the moral and political reasons for fighting will be evident, while the prospects of swift and full success are clearly not. This leads us to the second and third categories mentioned in my introduction: succeeding in reaching limited goals on the one hand and what we might term psychological success on the other.

Let us look at some historical examples.

When Norway was attacked by Nazi Germany in April 1940, the likelihood of full success in fighting back the occupation was minimal, given the strength and determination of the German forces and the relative weakness of the Norwegian military. However, the Norwegian King’s and government’s refusal to accede to Germany’s demand for an immediate stop to all fighting, including full collaboration with the occupying forces, served two purposes: firstly, to make the process of occupation harder and costlier by destroying crucial infrastructure and allowing the escape and evacuation of key resources and people, and secondly, to signal to one’s own population and the world a willingness to stand up and fight against an oppressive, aggressive regime.

In Northern Norway especially, German troops struggled. The terrain and the fact that Norwegian efforts were strengthened by an influx of troops from the United Kingdom, France, and Poland, led to Germany’s first military defeat of the war when Narvik was recaptured from Nazi forces in late May 1940.

This case, however, is interesting because by the time the recapture of Narvik took place, the decision had already been made to withdraw allied forces for redeployment in France and in the defense of Britain. There was thus no realistic scenario in which the city could be held for long. Why, then, expend the enormous effort of taking the city and defeating the German forces? In allied leaders’ minds, this was a case of showing one’s capabilities and willingness to fight to Norway’s own population, the allies, and to the enemy. Arguably, despite the Germans regaining Narvik in early June days after their initial defeat, the campaign was a huge tactical and psychological success, most likely leading German High Command to give up the idea of a naval landing in Britain (Haymes 2005).

The story of Norway between April and June 1940 is thus one of succeeding in reaching tactical aims combined with a signaling of one’s ability and intention to fight, in spite of a limited likelihood of succeeding in driving the invasion back.

Greece’s resistance to Italy’s attempted occupation in the fall of 1940 and the subsequent German invasion in 1941 tells a similar story. As a result of fierce Greek military mobilization and resistance, the Italians—against the odds, in the view of Mussolini, although the invasion was poorly planned and executed—were outnumbered and had to give up the invasion and withdraw, leading Germany to commit forces in order to take control of the Southern Balkans. This took up great resources and significantly delayed the already planned attack on the Soviet Union, decisively weakening the chances of German success there. Arguably, it also gave the Greek population a strong sense of purpose as they suffered horrific occupation under Nazi rule (Osborn 2018).

These are, in other words, cases of calculating one’s likelihood of success using a different measuring stick than full victory in the shorter term. Careful deliberation is made as to the costs of not defending oneself, both along the lines of tactical war aims, such as an overall weakening of one’s enemy or the destruction of crucial infrastructure, as well as psychological and political signaling of how one is seen to react to invasion and devastation.

The question of losses and costs looms large, however. In such cases, is it morally and politically right to engage in and continue the fight if losses are bound to be significant while eventual victory is highly uncertain? How much value should be attached to limited war aims and psychological boosts when the likelihood of decisive, overall success is minimal? I will come back to this question below.

For now, we can conclude that the Norwegian and Greek WWII cases indicate that one can abide by the criterion of reasonable likelihood of success even if full or guaranteed victory, at least in the shorter term, is very unlikely, as long as important tactical or psychological war gains are reached, and one’s definition of success is adjusted accordingly.

Empathy and the Problem of Incomplete Knowledge

In the film Fog of War (Morris 2003), former US Defense Secretary Robert McNamara shares eleven basic lessons based on his dramatic experiences from decades of engaging in war, the first being “Empathize with your enemy.” It is relevant with reference to both the Cuban Missile Crisis (in which case President Kennedy alongside McNamara succeeded in understanding the intentions and wishes of the adversary, thereby avoiding war and potential nuclear disaster) and the Vietnam War (in which case McNamara realized several decades later that the US did not correctly divine the intentions of the counterpart, thereby escalating rather than subduing the conflict).

This reminds us of yet another deep-seated challenge inherent in the reasonable likelihood criterion: It is utterly dependent on what one’s enemy is doing, thinking, and planning, as well as the resources at the enemy’s disposal and their willingness to use them. When these factors are understood rightly and calculated into one’s behavior, the diplomatic avenues to avoiding or deescalating conflict will be significantly easier to access, and one’s calculation of whether military victory is likely will be much more accurate. Many would say that the lack of such an understanding, which will normally pertain, makes the criterion deeply problematic.⁵

In short, calculating the likelihood of success—of any kind—is dependent not only on one’s own military strength and planning but on the strength, resolve, and reaction of other parties (most notably one’s enemy, but also one’s own troops and population), and one’s knowledge thereof. Avoiding war and finding paths towards peaceful resolution of conflict will, in the same way, depend on finding ways of empathizing with and understanding the underlying thought structures and motivations of other involved parties, including but not limited to one’s enemy. For instance, what I have called the psychological success of inspiring pride and a willingness to fight among one’s own troops and populace, as well as among one’s allies, clearly depends on the impression created by one’s resolve and one’s actual fighting. The problem is, of course, that impressions can change, and fatigue can set in. In short, to predict the likelihood of success—whether total or partial, political or psychological—is notoriously hard.

This means that one’s definition of success, and one’s likelihood of achieving it, is intricately tied up with information and insight. If one elects to mobilize and deploy a significant troop size in order to defend one’s realm rather than, say, entering into negotiations, it should, ethically speaking, be based on an idea of the kind of success that can possibly be achieved, its likely costs, and the alternatives available.

The Price to Pay

As Frances Harbour (2011, 236) puts it: “Fighting with only a small probability of success is also a problem because armed conflict—win or lose—always causes harm.” Indeed, the terrible hardships people suffer during war can make one ask whether any cause is worth fighting for if a refusal to fight violently can hinder those fatalities. Put differently: Without full assurance that success can be reached without enormous human losses, resort to armed force is morally deeply problematic. Fighting simply to delay the inevitable or as a form of virtue or valor signaling would be impermissible according to this line of thought.

As an answer to this challenge, several reasons can be put forward for nonetheless fighting. Three can be gleaned directly from our definitions of success above: (1) One may see that full victory is actually possible, thereby, in the most dramatic case, securing the survival of one’s nation and one’s people against a brutal enemy. If so, it would seem—except from a purely pacifist standpoint—that the price of the sacrifices would, in most cases, be worth paying, especially if the likelihood of success is significant. (2) One may, like the Norwegians or the Greeks during WWII, inflict on an unjust enemy severe losses, which, in the longer run, will weaken the enemy’s chances of winning. Even this could be worth the sacrifice, provided the evil represented by the enemy is significant and dangerous. (3) By taking up arms and making sacrifices, one becomes a witness—to oneself and others—testifying to the value and importance of strength, valor, and dignity, inspiring others not to give in to tyranny and oppression.

Indeed, if the victory of the enemy is likely to lead to the imposition of brutal tyranny, one may accept significant sacrifices simply because the costs of defeat in terms of suffering and lives lost would be even worse, maybe much worse, thus using a consequentialist calculation. Nazi victory in Europe would arguably have imposed such hardships on the European population and by extension, the world’s population. Thus, the great, almost inhumane costs of fighting were somehow worth it. On the other hand, committing enormous resources and suffering terrible losses to hopeless causes so that all the defeats and hardships merely end up coming on top of what one would have experienced anyway seems callous.

Again, we simply do not know beforehand. That, however, brings us back to the imperative of gathering relevant information. In cases where we, with hindsight, can judge that we, with better and deeper anthropological and cultural insight, in addition to thorough intelligence on military and political strengths and weaknesses, could have won more easily or could have avoided the entire conflict, we are forced to ask whether the initial commitment of armed force was justified. Indeed, we can ask whether the extremely costly—and at least in the former case (arguably in both), ill-fated—interventions in Afghanistan from 2001 and Iraq from 2003 could have been either avoided or carried out very differently had one realized earlier that there was little hope of any real, full-fledged military success, whether strategic or tactical, political or psychological. The same obviously applies to Vietnam in the 1960s. However, in all these cases, the stakes were portrayed to politicians and the populace as so high that a failure to fight would have unacceptable consequences. And so, thousands upon thousands of lives were, in essence, sacrificed. A much more rigorous application of the likelihood of success criterion, in spite of all the criterion’s shortcomings and challenges, could have led to very different results.

Hence, we realize that the reasonable likelihood criterion is, at its core, a criterion calling on us to define our criteria for success based on thorough insight and knowledge of the case at hand.

Conclusion

Two of the cases mentioned above—Norway and Greece during WWII—inspire admiration as well as a realization that success can be many things. A high and preferably imminent likelihood of full-scale success in vanquishing a brutal enemy is not necessary for a battle to be ethically acceptable if other, tangible successes can be secured, not least if they are related to the long-term defense of crucial values and can be achieved at a reasonable cost.

Yet, making decisions that sacrifice the lives of thousands without knowing that they serve a higher, meaningful purpose is arguably a political sin of epic proportions. As the US Catholic Bishops put it in their 1983 pastoral letter on war and peace, the purpose of what they call the probability of success criterion “is to prevent irrational resort to force or hopeless resistance when the outcome of either will be disproportionate or futile” (Reichberg, Syse, and Begby 2006, 673).⁶ This summarizes succinctly what my remarks above have hoped to convey: that defining what one hopes to achieve, calculating its likelihood with open eyes, and constantly weighing the pursuit of success against the costs of pursuing it when the likelihood of success is limited, lies at the heart of what the reasonable likelihood criterion means.

For the Ukrainian forces currently fighting against the brutal Russian invasion, success is measured in terms of all three definitions above. For them, that means—at least at the time of writing—that a suggestion that the costs are too high and that they should immediately enter into negotiations will be seen as wrong-headed since it will indicate that the value of fighting for one’s country and for one’s full rights to territorial integrity are denigrated, and by extension that other parts of Europe could open themselves to similar aggression. According to Ukrainian and NATO leadership, all of this can be avoided through a continued fight. To others, such a policy will lead to a hopelessly protracted war that could end in a stalemate, costing thousands of lives on one’s way there.

The situation is tragic, but it does illustrate the value—and the great complexity—of the reasonable likelihood of success criterion.⁷

Acknowledgment

I am indebted to the work of the late Frances Harbour on the reasonable likelihood criterion, as well as valuable conversations with my good friend Angelika Kruse-Jensen about her childhood memories from Greece of—and later lessons learned from—the courageous Greek campaign during WWII.

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Henrik Syse

Henrik Syse (Dr. Art.) is Research Professor at the Peace Research Institute Oslo (PRIO), Professor of Peace and Conflict Studies at Oslo New University College, author and editor of many books and articles, and a much-used public speaker. He also teaches regularly at the Norwegian Defense University College, at the University of Oslo, and at several other institutions of higher learning, and he is Chief Editor (with James Cook) of the Journal of Military Ethics.

Notes

1 Churchill’s famous portrayal of the evacuation from Dunkirk as a success comes to mind.

2 By “prudential” just war criteria I have in mind proportionality and last resort in addition to reasonable likelihood of success.

3 For one of the originators of this criterion within the just war tradition, Francisco Suárez (1548–1617), drawing not least on the work of Cajetan (1468–1534), the largest possible ascertainment of victory is a precondition for legitimate warfare, with the caveat that full knowledge of what will happen is not attainable. Suárez here emphasizes the difference between a war of necessity and a war of choice, putting purely defensive wars in the former category. In the case of defense, one may fight even with very slim chances of success, given that the war has already broken out and one has a rightful claim to defend oneself, whatever the odds. (See Suárez, Disputation XIII: On War, Section IV, in Reichberg, Syse, and Begby 2006, 347–353.) Suárez thus belongs to a school that holds offensive wars to be potentially just, as long as they serve a just cause and live up to the other just war criteria, one of which is reasonable likelihood of success. This also means that a just cause has to be present, and this cause must be linked to the danger of “a grave injury that cannot be avenged or repaired in any other way (ibid., 347). Hence, wars should not be initiated without it being a reaction to some wrongdoing, making the category of justified offensive wars if not defensive, then at least reactive.

4 By this I do not mean to imply that victory was considered absolutely certain. The Iraqi army was the world’s fifth-largest at the time, and many parts of its military had considerable experience from the Iran–Iraq war (1980–1988). However, the overwhelming force of the United States and its allies, backed up by widespread international support (including a UN mandate), and concentrated around a clear aim – all of which constitutes the basis of what became known as the Powell Doctrine (named after then-chairman of the Joint Chiefs of Staff Colin Powell) – was seen as a strong indicator of decisive success.

5 See the interesting and important discussion in McLaughlin 1998, esp.76–78.

6 See also Luzárraga 2022. The pastoral letter, God’s Promise and Our Response, contained a number of thought-provoking definitions of core just war criteria.

7 See Reichberg, Tønnesson, and Syse 2022 and 2023; and Holtsmark 2023 for a debate about the prospects of succeeding militarily and with negotiations respectively in Ukraine.