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WHEN TO OCCUPY
The Threat Environment
The most successful occupations in history were in many ways the most ambitious and radically transformational. They were also among the most surprising. The United States and its allies fought lengthy and vicious wars against both Germany and Japan, yet were then able to occupy both countries and transform them from fascist, militaristic, and highly nationalistic enemies into democratic and peaceful allies. There is a simple explanation for why these occupations, despite their apparent difficulty, were able to succeed while others have failed: the threat environment of the occupied territory. By âthreat environment,â I mean both external threats and internal threats that may challenge the security, survival, and integrity of an occupied territory. In postwar Germany and Japan, the presence of an external threat, the Soviet Union, perceived as a threat by both the occupied population and the occupying power, created conditions conducive to occupation success. In other cases, where occupied territories have either faced an internal threat to their integrity or where no threat has been perceived, occupations have been less successful.
The Threat Environment
Recalling that a successful occupying power must placate the occupied population and maintain its own commitment to an occupation, the influence of the threat environment on occupation success is best understood by examining the perspective of both the occupied population and the occupying power.
The Occupied Population
When an occupied population perceives that another country poses a threat to its future security, it will welcome an occupying power that is both willing and able to protect it from that threat. As a consequence, the occupied population will offer little resistance to the occupying power, allowing the occupier time to rebuild political and economic institutions within the occupied country and create conditions conducive to a successful withdrawal. Nationalist populations are willing to suppress their desire for self-determination if doing so allows for protection from an external threat.1
Occupied populations determine their external threat environment by assessing the relative threat posed by the occupying power as opposed to other third-party states. In some cases, the occupying power itself will appear to pose the greatest threat to the nationalist desires of the occupied territory. In these cases, the occupied population will reject the occupation. In other cases, the occupied population may perceive another third party as the greatest threat to their long-term self-determination. Assessments of threat are based on the capabilities and intentions of the states involved. To measure relative threats, occupied populations are likely to examine the ideology and track record of the potential threats: Does a power typically restore sovereignty to other societies that it may have occupied? Is the future promised by the occupying power more attractive than the alternatives?
Occupied populations are less willing to suppress their nationalist instincts when the occupying power does not offer it protection from an external threat. The population will see less need for the occupation and will be more likely to resist the occupation. Such resistance may persuade an occupying power either to react violently and further antagonize the occupied population or to evacuate the occupied territory prematurely. In either case, the lack of an external threat contributes to the ultimate failure of the occupation by making it more difficult for the occupying power to accomplish desired reforms during the occupation.
An occupied populationâs views about the protection offered by an occupying power are likely to be affected by three different factors. First, the composition of the occupied population may determine whether or not an external threat is perceived. In a state with many different national groups that have a history of conflict between them, it is unlikely that all of the groups will agree on whether the greatest threat to their self-determination is posed by the occupying power or by some other third-party threat. In particular, groups within a state are unlikely to agree on the most compelling threat if at least one of the groups has an affinity with a neighboring and potentially threatening state, seeks to dismantle the occupied territory into more than one state, or aims to gain disproportionate control over the territory. Even a minority population can undo an occupation if it allies itself with an external threat or if it perceives the occupying power, not another foreign country, as the greatest threat to the security of the occupied country. Whereas, then, the population and the occupierâs interests may coalesce around a commonly perceived external threat, an internal threat to the coherence of the occupied territory is more likely to lead to occupation failure.2
Second, the level of external threat is determined not only by the presence of a nearby aggressive power, but also by the vulnerability of the occupied territory. Threat is a relative variable that is determined not only by the nature of external powers, but also by the status of the occupied territory itself. The threat posed by the capabilities of an external power is exacerbated when the occupied territory itself is particularly weak. Occupied territories left prostrate and defeated by the conflict preceding the occupation are likely to be more vulnerable to potential predators that are looking to capitalize on the weakness of the state. Destructive conflict may also leave the occupied population less capable of mounting a violent, determined opposition to a postconflict occupation. Other occupied populations that feel liberated and less in need of protection, rather than defeated and vulnerable, are likely to feel less threatened and, therefore, resist occupation.
Third, threat is not simply a structural variable determined by the presence of external powers. The initial absence or presence of a powerful external threat is significant, but perceptions of threat can be either reinforced or transformed by the strategies that occupying powers pursue once an occupation is underway. Thus, it is useful to distinguish between initial perceptions of threat at the outset of an occupation and subsequent perceptions of threat once an occupation is underway. In the next chapter, I examine how the occupied populationâs initial perception of threat affects the strategic choices of occupying powers and how those strategies, in turn, affect the occupied populationâs subsequent perception of threat.
The Occupying Power
An external threat also persuades an occupying power to maintain its commitment to an occupation. Occupying powers are continuously tempted to evacuate the occupied territory. By doing so, they may conserve resources and end their involvement in a foreign country. Unless an occupying power is seeking empire, it should want to terminate an occupation, not prolong it. The pressures to end an occupation can be intense. On the domestic front, groups opposed to the occupation may argue that the occupation is both unwise strategically and an unnecessary expenditure of vital national resources. If the occupied population violently resists occupation, then the pressure to end the occupation is likely only to increase as the death count among occupying soldiers continues to rise.
An external threat provides a justification to an occupying powerâs domestic audience for prolonging an occupation. Occupying powers have an interest in defending an occupied territory from an external threat. Otherwise, the cost of intervening in and occupying the territory in the first place will have been wasted. When an external threat is present, the leaders of an occupying power can better persuade their domestic audience that a longer occupation is necessary. In particular, when the occupied territory is perceived as vulnerable to predators as a result of the preoccupation conflict, the occupying power may feel compelled to protect that territory. Less vulnerable territories will likely appear less threatened and, therefore, less worthy of the costs of occupation.
When either an external threat is absent or the occupied territory is beset with internal threats, it is more likely that the occupying power will face pressures to end its occupation. Internal threats raise the prospect that an occupying power will become entangled in a costly and unproductive civil war. Domestic audiences will not see the value in prolonging a dangerous and costly occupation when it requires becoming a participant in another countryâs civil war. These pressures may tempt an occupying power to end an occupation prematurely without having established the conditions for long-term stability.
In sum, the most important predictor of occupation success is a favorable threat environment: the presence of an external threat to the occupied territory from which the occupying power is willing and able to protect it. Most often, the threat perceived by the occupied population and the occupying power will be the same, common threat. In theory, a successful occupation could result from a threat environment in which the population perceives one threat and the occupying power perceives another. In this unlikely case, the occupying powerâs presence may still provide protection to the occupied population even if two different threats are motivating the population and the power.
When the threat environment is unfavorableâan external threat is absent or the primary threat is an internal threatâoccupation is less likely to be successful. This analysis reveals two important auxiliary hypotheses. First, occupation is more likely to succeed in territories that have been left prostrate and vulnerable by the preoccupation conflict. Weak postconflict states are more prone to predatory behavior by other neighboring states. Vulnerability amplifies the threat posed by any external power. Second, the occupation of geopolitically significant territory is more likely to succeed. Such territories are both more likely to be threatened and more likely to generate a commitment from an occupying power to offer protection than territories on the periphery of the international system that are less likely to be threatened and that are perceived to be of lesser value.
Evidence on the Threat Environment
To evaluate the effect of the threat environment on occupation success or failure, I present two forms of evidence. First, in Table 1.1, I code each of the thirty cases of military occupation since 1815 for the threat environment and examine whether these factors correlate with success or failure. Second, to more closely evaluate the central hypothesis on external threat, I examine two cases that represent ideal types: the occupation of western Germany after World War II and the U.S. occupation of Haiti from 1915 to 1934.
Table 1.2 summarizes the data set with regard to the threat environment argument. Appendix 2 provides a slightly more detailed discussion of the threat environment in each case. In all five of the cases in which an external threat was present, the occupation succeeded. In five of the seven cases of occupation success, the occupied territory faced an external threat. The only occupations that succeeded without such a threat present were the allied occupation of France after the Napoleonic wars and the Soviet occupation of northern Korea after World War II. The allied occupation of post-Napoleonic France was a multilateral occupation that quickly restored the prewar monarchy and aimed to do little more. Although the French population merely tolerated rather than welcomed the occupation, the allied powers were able to accomplish their goal relatively quickly before both they and the population lost patience with the mission.3 Few cases of occupation since have attempted to restore either a monarchy or a prewar regime. In the next chapter, I discuss the other outlier, the Soviet occupation of northern Korea, which succeeded primarily because of an effective strategy of coercion that overcame the initial unfavorable threat environment.
Of the fifteen cases in which there was no external threat to the occupied territory, ten (67 percent) failed and only two fully succeeded. Further, in four of the six cases of occupation in which there was a major internal threat to the occupied territory, the occupation failed and the other two achieved only mixed success. In theory, one could also find cases with both an internal and an external threat, but unsurprisingly, there are no cases in the data set that featured both an internal threat and an external threat that was perceived by a strong majority of the occupied population. If the population is divided internally, then it would be surprising to find that population agreeing on the threat posed by an external power. All of these findings are consistent with the hypotheses presented above.
To further evaluate the importance of the threat environment, I present two detailed case studies. These cases represent prominent types of cases in the data setâone in which the threat environment was propitious for occupation success (the allied occupation of western Germany after World War II) and one where the threat environment augured occupation failure (the U.S. occupation of Haiti from 1915 to 1934). The German case is selected beca...