New technologies present opportunities, and dangers too, to send a greater diversity and range of signals during interstate crises. Nations could use cyber attacks to target each other’s armed forces more precisely, and hence reduce direct casualties to both military personnel and civilians. While sending that message would inflict harm, it could avoid the casualties and physical destruction of a kinetic attack. Cyber attacks might reduce the collateral harm to civilians by disrupting only military communications networks or stealing only classified intelligence. While cyber attacks certainly could cause widespread harm, such as cutting water and electricity services to civilian populations, they could also simply disrupt a government’s command-and-control of its military assets. Even if deployed against civilian targets, cyber weapons could still offer more precise and controlled power than a kinetic weapon.
The anarchy of the international system creates a second obstacle to cooperation. Even with perfect information, nations may still refuse to reach a peaceful settlement because they lack confidence that their opponent will keep its promises. They may understand that they will both be better off by avoiding war, for example, but nations may not trust each other to obey the agreement in the future. This problem will prove particularly acute in situations where a settlement changes the status quo between states or where rapid changes are affecting the balance of power.66 One nation will find it difficult to trust its opponent to keep a promise if the latter will become even more powerful as a result of the agreement. New weapons technologies might provide new ways to increase commitment to an agreement. It provides states with more measured ways to sanction nations to stop violations, short of terminating an agreement altogether. Precision cyber and drone attacks provide more steps of coercion beyond diplomacy and economic pressure but are short of conventional armed conflict.
A critic might argue that without international regulation of these new technologies, the risk to civilians will increase. Nations at war, however, will have an incentive to distinguish between military and civilian targets to the extent allowed by the capabilities of weapon systems. Rational nations should seek to contain the harms of war in order to maintain the conditions for peace and to preserve the value of the civilian economy in the postwar period.67 Defenders in a war do not want to kill their fellow citizens or harm their own territory, although they might destroy civilian property to prevent it from falling into the hands of the enemy. Conversely, invaders will have no interest in ruining the object of their aggression. Reducing civilian casualties may also encourage an end to conflict. Targeting civilians and destroying non-military resources may harden nations at war and make a diplomatic compromise more difficult. The unexpected carnage of World War I, for example, made peace restoring the status quo ante politically impossible for both the Allied and Central Powers.
Nations have long pursued indirect coercion against civilian populations in war. As we will describe more fully in the next chapter, they have often turned to economic sanctions to conduct hostilities short of armed conflict, or in conjunction with active hostilities. These sanctions pursued the objective of weakening the support of the civilian population for a regime’s military policies. In World Wars I and II, the Allies conducted economic warfare against Germany and its allies by levying a blockade of civilian shipping.68 After the wars, the U.N. Charter even expressed a preference for such tactics by authorizing the Security Council to impose “complete or partial interruption of economic relations and of rail, sea, air, postal, telegraphic, radio, and other means of communication” in the case of a threat to international peace and security.69
Economic warfare serves the same objectives as the approach described here for cyber and robotic weapons. First, it provides nations with a way to send signals in international bargaining through the gradual escalation of coercion, just as western nations used sanctions to bring Iran to the negotiating table over its nuclear program. Second, embargoes pressure civilian populations to change the policies of their leaders, or even the leaders themselves. While nations such as Great Britain and the U.S. have argued that embargoes only blocked goods that might contribute to an enemy war effort, the complete embargoes that prevailed during the World Wars seemed equally, if not more, directed against civilians. Perhaps new technologies, when employed as steps in the escalation of force, will also be understood as more akin to economic warfare than conventional bombing.
Limiting the use of force in a war bargaining situation can have several harmful effects. First, narrowing the range of targets only to military objects could have the effect of escalating the damage of signaling. In a crisis, nation A may want to send a signal that inflicts a certain cost on nation B. With a broader base of civilian targets, nation A could choose a relatively low level of harm to produce the desired level of coercion. Temporarily knocking out the electricity supply to the capital city, for example, will cause inconvenience to a large number of civilians. To produce the same level of harm upon a smaller base of military personnel and assets will require a higher level of force. Attempting to coerce nation B—consistent with a broad approach to distinction—might require nation A to attack and potentially destroy nation B’s military targets and kill military personnel. Limiting the universe of targets to purely military sites could even provoke extreme crises by encouraging nations to launch vulnerable offensive weapons first, before they themselves are attacked. This “use it or lose it” incentive could force early and extreme escalations of a crisis into a military conflict.70
A prohibition on certain targets could also raise the chances of miscommunications that might have the unintended consequence of leading to war. Barring attacks on civilian assets will reduce the number of possible targets; only military personnel, facilities, and assets would be fair game. This strategy will limit the means of coercion between states. Only military means will prove effective against military units. It may also prove impossible, even with highly precise guided munitions, to tailor non-lethal uses of force solely to strike military units. Disrupting electrical supplies or destroying fuel stocks may exert low-intensity coercion against an opposing military, but it may also hurt civilians and non-military installations equally, if not worse. Other types of non-lethal tactics, such as cutting off access to the international financial system, may not have any direct effect on military targets at all.
Limiting force only to military targets may encourage the development and use of more destructive munitions. If nations expect that coercion will only take the form of attacks on their militaries, they will make military targets more difficult to attack. They may improve their military defenses to the extent that the attacking nation must deploy a significantly greater level of force to prevail. A defending nation, for example, might place critical facilities underground or in bunkers. It might even disperse critical military assets among the civilian population. Attacking military targets may force a nation to undertake an act of greater force to seek resolution of a dispute, while using lower levels of non-lethal force involving civilian targets might have equally communicated its message.
Reducing the number and types of targets and limiting the means to pursue them would increase the odds of war. Imperfect information can lead rational states to miscalculate. If there are further steps to convey reliable information, nations will have more accurate information on the expected values of war. That information will allow them to consider settlements before making the fateful decision for war. The more steps up an escalatory ladder, the more opportunity nations have to jump off before they reach the stage of armed conflict. On the other hand, limiting the ability of nations to communicate will reduce their ability to reach settlements of their differences. If nations have less opportunity to credibly signal information to each other, the chances of miscalculation and war will increase.
The twenty-first century has brought new types of security challenges to the United States and its allies. Where the last century saw worldwide war between continent-spanning alliances, today the threats to peace come from regional powers, rogue nations, terrorist groups, and civil wars.