The United States has long fielded the world’s most capable armed forces. It spends more on its military than the next nine nations combined, of which five are U.S. treaty allies.[1] It fields more active-duty military personnel than any country other than China,[2] and its weaponry and technological capabilities are peerless. U.S military superiority has helped deter major power wars, secure the global commons, and maintain the global order for many decades, and it continues to do so today.

Yet, every strength has a corresponding weakness, every advantage a corresponding vulnerability. Perhaps paradoxically, this conventional military dominance means that few adversaries are likely to directly challenge the United States with the use of force, since doing so risks complete military defeat. As Army Lieutenant General H.R. McMaster has often quipped, “there are two ways to fight the U.S. military – asymmetrically and stupid.”[3] Fighting asymmetrically can mean fighting at the lower end of the conflict spectrum, through terrorism and insurgency. But it also can mean fighting in what has become known as the “gray zone,” which may not involve military forces at all.

Gray zone conflicts are neither war nor peace, but instead lie somewhere in between. As I’ve written elsewhere, “their defining characteristic is ambiguity – about the ultimate objectives, the participants, whether international treaties and norms have been violated, and the role that military forces should play in response.”[4] Such ambiguities enable adversaries to pursue their interests while staying below the threshold that would trigger a military response – and, if they remain ambiguous enough, they might avoid any response. They are therefore a smart approach for revisionist powers, who wish to change the current U.S.-led international order to better serve their own interests. According to Hal Brands, the goal of gray zone approaches “is to reap gains, whether territorial or otherwise, that are normally associated with victory in war. Yet gray zone approaches are meant to achieve those gains without escalating to overt warfare, without crossing established red-lines, and thus without exposing the practitioner to the penalties and risks that such escalation might bring.”[5]

From the Gray Zone to Unrestricted Warfare?

Much of the recent interest in understanding gray zone conflicts has been sparked by the two clearest cases we see today: Russia’s intervention in Ukraine, and Chinese activities in the South China Sea. Russia’s annexation of Crimea in early 2014 and its subsequent activities in eastern Ukraine fit the definition very well. The Russian presence there did not involve soldiers in military formations, but instead involved “little green men:” soldiers and other agents without any uniforms, insignia, or other identifiable markings that enabled Russia to deny any involvement. Today, almost two years later, the Kremlin continues to publicly deny its support for the separatist movement while the fighting continues on.

In the South China Sea, China’s increasingly assertive behavior also fits the definition of a gray zone conflict. China’s maritime presence and willingness to challenge international boundaries and norms have been increasing for the past several years, but have grown bolder in the past 18 months. China completed land reclamation efforts at the three largest outposts in the South China Sea early last year, and is now focusing on building infrastructure. China claims that the construction is for peaceful purposes. Yet, the airfields on each of those three outposts are already long enough to land most military aircraft, which means that they could be used as a power projection platform to enforce the contested Chinese claims throughout the entire South China Sea.[6] At the same time, China has stepped up its maritime patrols, employing ships from its coast guard and maritime militias[7] rather than its navy. That enables China to claim that these are civilian patrols enforcing economic claims rather than anything military in nature, thereby seeking to avoid a strong escalatory response. And, in large part, that strategy is succeeding. In October 2015, the United States began conducting periodic freedom of navigation missions in the South China Sea,[8] where U.S. ships sail within 12 miles of the artificial islands to demonstrate that the United States rejects any maritime claims emanating from those islands. But it is hard to imagine that the U.S. response would remain so limited if Chinese warships were conducting those patrols instead.

But these two examples may be the proverbial tip of the gray zone iceberg. Russia is sending military personnel to eastern Ukraine, even though they may not be explicitly identifiable as such; in the South China Sea, Chinese civilian state organizations are behaving like military forces. As complicated as these cases are, they are at least recognizable as a form of conflict that could potentially involve a military response. But that may not always be the case – and in fact, that may become increasingly uncommon in the future.

If we accept Brands’ statement that gray zone conflicts are designed to reap gains that are normally associated with victory in war yet without the penalties and risks of military escalation, then the most attractive gray zone strategies will be those that avoid activities that might be at all recognizable on the conflict spectrum. One of the best possible outcomes for a gray zone adversary would be to achieve those goals without the target state even knowing that such a conflict is taking place, since then there is no chance of escalation. Of course, such strategies are not risk free; there is always the chance that the target may retaliate once its leaders realize what has happened. But at that point, the costs of doing so will be much higher, since the target state would have to actively undo a fait accompli and change the new status quo. And it may be very difficult to build public support (in democracies, at least) to marshal the different elements of national power – up to and including military force – in response.

And therein lies the conceptual weakness of the gray zone, or, more accurately, of our understanding of 21st century conflict. It is not clear when gray zone conflicts stop being conflicts at all and start becoming something else, something that we don’t yet understand or have words to describe. How do we think about adversary actions that previously could only be achieved with military force, but may now be achievable through other, more insidious means – especially in an age of rapidly diffusing technological and cyber capabilities? Perhaps, the best way to conduct war with the United States is not to conduct war at all, to avoid using military forces and use other means to try to achieve the same goals that in an earlier era could only be achieved by victory in war.

In 1999, two Chinese colonels published a book called Unrestricted Warfare,[9] which went largely unnoticed in the United States outside of a small circle of military analysts.[10] Their argument, which was explicitly framed as a response to the overwhelming U.S. victory in the 1991 Gulf War, was that modern warfare would no longer be primarily a struggle defined by military means. Instead, war had evolved to “using all means, including armed force or non-armed force, military and non-military, and lethal and non-lethal means to compel the enemy to accept one’s interests.” No longer would there be a distinction between soldiers and civilians, because society itself would be the battlefield. The number of new battlefields would be “virtually infinite” and could include environmental warfare, financial warfare, trade warfare, cultural warfare, and legal warfare, among many others. They wrote about assassinating financial speculators to safeguard a nation’s financial security; establishing slush funds to influence opponents’ legislatures and governments; and buying controlling shares of stocks to transform the target’s major news outlets into tools of media warfare. According to the editor’s note in the English translation, one of the authors later argued in an interview that “the first rule of unrestricted warfare is that there are no rules, with nothing forbidden.” That vision clearly transcends any traditional concepts of war and peace.

Those views may have seemed farfetched when they were published almost 18 years ago, but a lot has changed since then – and nothing more so than the explosive growth of the internet and cyber technologies. Today, the internet dominates all aspects of global trade, economics, communications, and even social relationships. That makes Unrestricted Warfare even more relevant today than when it was published – because waging war without limits is now simpler and easier than its authors could possibly have envisioned. In 1999, the ability to assault all elements of an opponent’s society seemed to require the resources or sponsorship of a powerful nation state. Now, an increasingly interconnected world allows adversaries at keyboards – not only states, but also disgruntled individuals and terrorist groups – to render geography irrelevant and strike at nearly any facet of another society without ever using or encountering military forces.

This does not mean that military force will become completely obsolescent. States will always need military forces to defend against foreign military threats, and as a possible response option against whatever they deem undue interference in their sovereignty. But taken together, the concepts of gray zone conflicts and Unrestricted Warfare suggest that our current conception of the conflict spectrum is increasingly anachronistic. We need to start thinking about conflict and warfare in a far more holistic way than simply as primarily military in nature. We need to develop a range of possible strategies and responses for a world where the distinction between war and peace may be very unclear – and may no longer be a meaningful distinction at all.

Back to the Present: Gray Zone Conflicts in the Age of Trump

The unexpected election of Donald Trump may make it more likely, rather than less likely, that the United States will face an increasing number of gray zone conflicts in the coming years. Much about his policies remains unknown; he is still in the earliest days of his presidency, and since his campaign rhetoric contained many contradictory statements, it is not yet clear how he will govern. Nevertheless, there are at least three early signs that, taken together, suggest that U.S. adversaries may find gray zone conflicts a particularly advantageous way to pursue their interests in the next four years and possibly beyond.

First, most of candidate Trump’s statements about America’s global role suggest an increased inward focus, not quite isolationism but certainly a retreat from the global engagement that has characterized U.S. foreign policy since the end of World War II. He repeatedly identified ISIS and radical Islamic terrorism as an almost existential threat to the United States, and his selection of retired Army Lieutenant General Mike Flynn as his national security advisor guarantees that view will be well represented within the White House. U.S. adversaries, especially state adversaries, may well calculate that the new president may be less likely to use force around the world. This is particularly true of Russia, since Trump has gone out of his way to praise Putin as a strong leader and vowed to strengthen the U.S.-Russian relationship. With a friendly administration in office, it would make little sense to counter the United States directly and risk escalation. It would be much smarter for Russia to continue and even expand its gray zone challenges, enabling Moscow to slowly but surely expand its influence throughout eastern Europe and perhaps beyond while retaining some plausible deniability. And Putin may be particularly emboldened by Trump’s rejection of the intelligence community’s finding that Russia not only interfered with the election but did so in ways that gave Trump an advantage. (This in itself may be a more complicated form of gray zone conflict, or even an example of unrestricted warfare; an outside power directly interfering in the selection of a foreign leader has traditionally involved at least some use of military or paramilitary force, and is often described as “regime change.”)

The same logic might apply beyond Russia as well. For example, Trump appeared to be taking a hard line against Iran during the campaign by promising to pull out of the six-nation nuclear deal. Yet, Iran would stand to gain quite a lot if the United States does pull out, as long as no new sanctions are put in place. It would be able to continue its nuclear program, even at a lower level, without incurring the economic challenges that led it to the bargaining table in the first place. The prospect of avoiding new sanctions might be low, but could still be enough to convince Iran to refrain from directly challenging the United States while still continuing or even expanding its support for its malevolent proxies around the world.

Second, Trump is and will likely remain an unpredictable president. Not only does he lack any experience in foreign and security policy, but it became clear on the campaign trail that he does not like being challenged and often lashes out in response. Trump’s overall orientation may make the use of force less likely, but as long as he continues to be viewed as an unpredictable leader, U.S. adversaries will still have to consider the possibility that any outright challenges to U.S. interests will be met with escalation – and not just moving step-by-step up the escalation ladder, but possibly jumping several rungs entirely. That will induce a sense of caution that will make it even more likely that U.S. adversaries will seek to challenge the United States indirectly rather than directly. Adversaries who wish to avoid the risk of any escalation, no matter how low, may choose to pursue their interests and objectives through indirect and deniable conflicts in the gray zone.

Third, candidate Trump repeatedly expressed skepticism about international institutions and multinational cooperation. This came through most clearly regarding NATO, especially when he suggested that the Article V collective defense commitment might not extend to allies who do not pay their fair share. That in itself may embolden Russia to try to expand its sphere of influence through gray zone conflicts in eastern Europe, perhaps even within the Baltic states. But this skepticism extends far beyond NATO and includes institutions such as the United Nations and the World Trade Organization as well as less formal forms of international cooperation. Why is this relevant for a discussion on gray zone conflicts? Because multinational institutions and fora uphold international norms (however imperfectly), reinforce partnerships among like-minded nations, and help promote global transparency. Much of their work is the unheralded and decidedly unglamorous collection and distribution of information – straightforward facts and figures about the nuts and bolts of international activity. To the extent that these institutions grow weaker, so do international norms and transparency. And that, in turn, makes gray zone conflicts an even more attractive option for U.S. adversaries. Weaker norms can be undermined more easily than strong ones, and weaker transparency makes plausible deniability even easier.

These trends thus suggest that gray zone conflicts will become more frequent and complex in the next four years and possibly beyond. The United States will almost certainly maintain its conventional military superiority during this time frame,[11] which means that U.S. adversaries will continue to seek asymmetric ways to pursue their interests. Growing cyber capabilities and other advanced technologies will increasingly enable them to do so in ways that previously required military force but no longer do. And the early signs from the new Trump administration will likely make gray zone strategies an even more attractive strategic choice for those who wish to challenge U.S. interests and threaten the open, liberal, and free global order that the United States has led and protected for the last 70 years.

[1] International Institute of Strategic Studies, The Military Balance 2016, London: Routledge, 2016, p. 19.

[2] Ibid., pp. 485-490.

[3] See Lt. Gen. H.R. McMaster, Ph.D., U.S. Army, “Continuity and Change: The Army Operating Concept and Clear Thinking About Future War,” Military Review, March/April 2015, p. 16.

[4] See David Barno and Nora Bensahel, “Fighting and Winning in the ‘Gray Zone,’” War on the Rocks, May 18, 2015.

[5] Hal Brands, “Paradoxes of the Gray Zone,” Foreign Policy Research Institute, February 5, 2016. Emphasis in the original.

[6] David Barno and Nora Bensahel, “A Guide to Stepping It Up in the South China Sea,” War on the Rocks, June 14, 2016.

[7] Andrew S. Erickson and Conor M. Kennedy, “China’s Maritime Militias,” Center for Naval Analysis, March 2016, https://www.cna.org/cna_files/pdf/Chinas-Maritime-Militia.pdf.

[8] See Sam LaGrone, “U.S. Warship Conducts South China Sea Freedom of Navigation Operation,” USNI News, October 21, 2016.

[9] Qiao Liang and Wang Xiangsui, Unrestricted Warfare, Beijing: PLA Literature and Arts Publishing House, February 1999, FBIS translation available at https://www.cryptome.org/cuw.htm.

[10] The rest of this section draws on David Barno and Nora Bensahel, “A New Generation of Unrestricted Warfare,” War on the Rocks, April 18, 2016.

[11] However, U.S. conventional superiority may well be challenged in the longer term, especially given the possible combined effects of constrained defense budgets, internal cost growth within the Department of Defense that limits the dollars available for combat forces, and the increasing capabilities of the Chinese military.