But all is not well with the gray zone. Problems with overstretching the definition not only persist, but they are getting worse. More importantly, while the gray zone was supposed to add nuance to our traditionally binary understanding of war and peace, it has simply become a reflection of it. These are not reasons to scrap the term. Rather, they are reasons to revisit the debate.
The gray zone has become untethered from any particular level of escalation. Herman Kahn’s work from over 50 years ago offers us the tools to wed it to one. The gray zone should characterize activities of only a moderate level of escalation, measured, à la Kahn, in terms of the “likelihood of eruption.” Assessed in this way, gray zone activity would be context dependent—and relative—and would be resistant to efforts to identify fixed characteristics of it.
The most common way to conceive of the gray zone is as an area on the spectrum of conflict just below the emergence of conventional military operations. Gray zone activities occur in this area and, as a recent RAND study argued, are “designed to change the status quo through steps that, while consequential, are nonetheless deliberately calculated to remain below the level that would trigger an armed response.” So defined, the gray zone subsumes essentially all state behavior, save that intended to start or fight a war. Analysts have recently used the term to characterize conduct as provocative as the invasion and occupation of an entire state by the regular forces of another and as pedestrian as participating in track two dialogues and allowing Canada to purchase maritime monitoring devices.
The conceptual stretching afflicting the gray zone stems from the traditional understanding of the spectrum of conflict. The most common way by which to organize the spectrum is by intensity of violence, but the gray zone is by definition characterized by an absence of violence or, at most, minimal levels of it. Lumping all non- or minimally-violent behavior together into the gray zone category renders it essentially synonymous with peacetime competition. It is no wonder then that Gen. (ret.) Joseph L. Votel, the former head of U.S. Central Command, has described the Cold War as a “45-year-long Gray Zone struggle.”
There is thus an urgent need to differentiate among activities meant to change the status quo without triggering an armed conflict. The most straightforward way to do so is by level of escalation. In his excellent 2015 study, Michael Mazarr sought to make such a distinction by contending that the gray zone must involve “strategic gradualism”—that is, “the slow accumulation of small changes none of which in isolation amounts to a casus belli.” He suggested, for example, that while grabbing half of another state’s territory would be inconsistent with such gradualism, “the swift appearance of a Chinese outpost on a barren and unoccupied rock in the South China Sea…would fit snugly” within it. The key, Mazarr argues, is “scale.”
Although intuitively appealing, the emphasis on scale is misleading. We can’t know in the abstract what will constitute a casus belli, but we can say with some certainty that it won’t always correspond to scale. While the “swift appearance of a Chinese outpost” in the South China Sea may not be a casus belli—as it was not when China established just such a presence on Mischief Reef in 1994—a similarly swift appearance of an outpost on one of the Senkaku/Diaoyu islands in the East China Sea almost certainly would be. Similarly, although Egypt’s occupation of the Hala’ib Triangle in 2000 did not lead to war with Sudan, an Egyptian operation executed in the same way targeting a far smaller percentage of Israeli territory likely would.
The Risk of Eruption
If the emphasis on scale is misleading, how should we differentiate among levels of escalation? Herman Kahn’s work on escalation provides a useful way forward in this regard. Kahn noted that the “likelihood of eruption”—that is, the risk that a violent conflict will emerge—was both a fundamental attribute of escalation and a reasonable metric of it. Using this standard, the gray zone should be characterized by a moderate level of escalation—by conduct with a moderate risk of eruption. Highly escalatory and negligibly escalatory behavior, on the other hand, should be considered outside of the gray zone. There are of course no bright lines differentiating probabilities of eruption, but accepting some degree of imprecision in this respect will not hamper our efforts to better circumscribe the concept.
The likelihood of eruption will, to some degree, depend on the challenger and what it’s doing. To a greater extent, however, it will hinge on the defender, the value it and its allies attach to the status quo, and their capacity to defend it. Where a capable challenger is undermining a status quo highly valued by a capable defender, factors such as the rivals’ force structure, the availability and effectiveness of crisis management mechanisms, and the perceived costs of backing down will bear on the likelihood of eruption. As such, what does and does not qualify as gray zone conduct cannot be determined in the abstract. Indeed, behavior that in one context falls within the gray zone, may not in another. When several hundred Indian forces entered Chinese-claimed territory at Doklam in 2017, they were conducting a gray zone operation. A similar effort by North Korean troops crossing the Demilitarized Zone would exceed the gray zone threshold.
How can we make this assessment? First, most Chinese forces in the area are stationed deeper inland, and none were garrisoned at Doklam, providing a large buffer between Chinese and Indian troop concentrations and ample time for crisis management. The Demilitarized Zone in Korea, on the other hand, is “the world’s most heavily guarded border” along which forces are highly concentrated and separated by only 2.5 miles. Second, because the tri-border junction around Doklam is poorly demarcated and the parties do not agree on its location, it is an area conducive to the use of salami tactics and the kind of transgressions—almost always peacefully managed—common along China’s southwestern boundary. The Demilitarized Zone, on the other hand, serves as a bright red line. It is ill-suited for territorial salami tactics and in the event that several hundred North Korean troops crossed it, their presence would almost certainly represent a profound and unacceptable threat to Seoul. Third, China and India have developed an “elaborate series of bilateral mechanisms,” honed over decades of border standoffs, that they were able to call on at Doklam. At the Demilitarized Zone, although there are hotlines linking the two sides, even when the North is picking up the phone, the rules of engagement are such that fire is exchanged when troops approach the border, to say nothing of crossing it. Last, Beijing’s control over its domestic media enabled it to minimize the domestic political costs associated with deescalating by claiming victory and shaping the subsequent narrative. If Seoul—and Washington—however failed to respond decisively and with force to such an incursion, they would pay enormous political and reputational costs, militating against peaceful resolution and elevating the risk of eruption.
Many of China’s and Russia’s challenges to U.S. freedom of navigation and overflight are properly considered gray zone operations. The most recent such episode involved a Russian destroyer coming within 35 yards of the USS Chancellorsville, compelling the latter “to maneuver to avoid collision.” Such encounters pose a non-negligible risk of eruption via inadvertent escalation. China’s 2012 seizure of Scarborough Shoal in the South China Sea was also a gray zone operation. While the dramatic asymmetry between Chinese and Philippine capabilities surely had a powerful deterrent effect on Manila, as claimed national territory, the reef was highly valued. During the initial stages of the incident, moreover, as the Chinese navy lingered over the horizon, it was the Philippine Navy’s flagship that was deployed at the site of the standoff. China’s ultimate seizure of the reef thus posed a plausible, but by no means overwhelming, risk of armed conflict. Although Russia’s annexation of Crimea is commonly cited as a gray zone operation, the occupation and annexation of “homeland territory”—as opposed to unoccupied offshore features—is among the most escalatory actions a state can take. As such, despite Moscow’s unconventional tactics and the asymmetry between Russian and Ukrainian capabilities, the risk that such an operation would lead to armed conflict was always high, and it should not therefore be considered a gray zone operation.
There are several salient implications stemming from the foregoing analysis. First, the framework established here dramatically narrows the scope of the gray zone, helping to combat the concept’s struggles with stretching. In addition to excluding behavior that poses a high risk of eruption, it also excludes a wide range of conduct at the lower end of the spectrum—e.g., “trade policies,” “strategic investment,” “propaganda,” and “general information diplomacy”—that is too often regarded as gray zone activity. Although there are surely extreme hypothetical situations in which such conduct might pose an elevated risk of eruption, for most states, most of the time they are simply the stuff of day-to-day international politics. They are unremarkable and pose a decidedly low risk of eruption.
Second, although the gray zone is often regarded as an area on the conflict spectrum immediately below the emergence of conventional military operations, this need not be the case. Because states can escalate beyond the gray zone without triggering a war—as illustrated, for example, by Nazi Germany’s invasion and occupation of Austria—we ought to acknowledge the existence of an area on the conflict spectrum between the gray zone and conventional armed conflict.
Third, efforts to specify characteristics of gray zone behavior are misplaced. Mazarr and others, for example, have suggested that the use of “unconventional tools” and “calculated ambiguity,” are essential aspects of gray zone behavior. Unconventional instruments, however, like conventional ones, can be employed below, within, and above the gray zone. The same can be said about intentionally ambiguous and unambiguous behavior. While unconventional tools and calculated ambiguity can be used by challengers to obfuscate and help mitigate a defender’s assessment of the escalatory extent of its behavior, they are in no way essential attributes of gray zone operations. The only essential characteristic of gray zone behavior should be that it pose a moderate risk of eruption.
Fourth, and relatedly, despite assertions that the gray zone is the preserve of revisionist states, nothing about the concept is unique to revisionists. It is an area on the spectrum of conflict in which any state can operate. In a new era of great power competition, the United States will need not only to defend against adversary actions in the gray zone, but also proactively operate within it.
If the gray zone is to contribute, and add nuance, to our understanding of the lower end of the conflict spectrum, the conceptual debate needs to be revisited. Circumscribing the term around the “likelihood of eruption” should help to more appropriately position it along the spectrum of conflict, redress some of the most egregious applications of the term, and point a way forward.
The author is grateful to Christopher Cairns for comments and suggestions on an earlier draft of this article.