states with the ability to use more precise, focused force to punish oppressive regimes intent on genocide. They can allow nations to pursue terrorists into lands inaccessible by ground or sea units. They can raise the costs on rogue states seeking WMD or rising powers seeking to upend regional stability. To fully understand the reasons why new technology may succeed, we will now examine a useful theory to explain why force may help in keeping the peace.
Using Force to Commit to Peace
In order to control these threats, nations must return to the use of force as a means of coercion. Great powers have long used force to pressure each other. Even in the twenty-first century, nations will continue to advance their interests, at times with conflict, and at other times with cooperation. New military technologies will make it feasible for nations to use force more often, rather than less, because they will be able to achieve their aims without triggering broader war. In this section, we turn our attention to one possible theory that could help explain why expanding the methods of force could encourage greater peace between the great powers.
We do not adopt this approach as the sole foundation for our account of war, technology, and law, rather, we develop it as a possible theory that supports our intuition that advancing weapons technology can lead to less conflict. This theory sees war as the failure of rational nations to reach a settlement of their disputes. The anarchy of the international system undermines the bargaining process because nations have uncertain information about their opponents’ capabilities and cannot trust them to keep their promises. More ways to use force could provide leaders with greater means of signaling their seriousness of will, military capabilities, and commitment to avoid war. That may justify the counterintuitive conclusion that new technology can bring more, rather than less, peace.
Our world might be safer if it were more actively policed, just as more active policing has reduced violent crime in American cities.55 The international system, however, lacks an effective supranational government that can stop violence in the same way that domestic institutions maintain law and order at home. Not only must nations use force more broadly in self-defense, but in the absence of an effective government they must also intervene to prevent threats to global welfare from weapons of mass destruction, terrorism, and aggressive authoritarian nations. Rivals such as Russia and China pose a tough challenge for this mission. Both nations enjoy the resources and militaries to place them in the rank of great powers. Their ambitions clash with U.S. interests, from Eastern Europe to the seas of the western Pacific. While their intentions may make them rivals of the United States, however, their own economic status gives them a great deal to lose. American power likely deters them from any direct, widespread conflict.
Critics, on the other hand, believe that new weapons could make the use of force cheaper, and hence war more commonplace. But we believe this view is mistaken. The ability to use force more precisely will prove a benefit to the international system. The signaling of resolve and capability through less destructive attacks can help avoid the worldwide conflicts that caused such grave human suffering and death in the twentieth century. Ironically, the availability of new weapons technologies should reduce the chances of great power war and lead to more settlement of conflicts.
If there is a place for coercion (as opposed to merely repelling attacks), however, the scope for resort to force must be enlarged. It will no longer be obvious that retaliatory measures must actually be limited to attacks on “military objectives.”56 Keeping the peace today requires a return to earlier understandings of the use of force. International law should allow nations to use force against civilian targets, so long as they do not involve lethal means of coercion. Recent efforts to apply a broad definition of the principle of distinction to twenty-first century conflicts should be relaxed, because they will have the unintended and perverse consequence of rendering war more likely and more destructive.
Even if our approach were to allow the great powers to suppress WMD proliferation, humanitarian crises, and terrorism, critics will worry that it will encourage conflict. Wider discretion in the use of force will result in more violence, which could increase the risks of war. Close attention to a promising theory of international crises, however, suggests that new weapons may actually reduce, rather than increase, the chances of war. Great powers will go to war when they fail to reach a negotiated settlement of their differences. They can bargain with each other using diplomacy, but when words alone fail, they must resort to demonstrations or even applications of force. New weapons provide states with the means to exert pressure at lower levels of destruction and casualties, which provides great powers in a crisis more opportunities to divert from escalation to settlement.
Rivalries will still endure and nations will still have disputes. But a promising theory of conflict suggests that rational nations should settle their disputes when the gains from cooperation outweigh the benefits of conflict. As Thomas Schelling argued, “Conflict situations are essentially bargaining situations.”57 Situations involving the possibility of armed conflict produce high incentives to avoid the losses from going to war.58 Nations can settle their disputes in a way that gives each side some benefit while foregoing the loss of life and resources due to armed conflict. This approach bears similarities to a law and economics analysis of litigation, where parties acting rationally and with full information should always prefer settlement to the great expense of going to court.59 Similarly, nations that have full information about military resources and political will should prefer an agreement instead of a conflict that wastes resources and will probably produce the same outcome.
International agreements serve as a means to resolve disputes between nations. Treaties can resolve border disputes, formalize the transfer of territory, or promise favored treatment for citizens and goods and services. Peace treaties recognize the end of a war. Nations, however, encounter significant obstacles to the enforcement of treaties. At home, parties can rely on a legal system, backed up by courts and police, to enforce a settlement. International anarchy, however, interferes with the ability of states to enforce agreements, despite their obvious benefits to both parties. Without international courts or police with effective authority to elicit compliance, a nation-state can renege on a treaty without consequence other than retaliation from other states.
This produces a classic prisoner’s dilemma.60 Nations might not enter into treaties because they do not trust their partners. This problem will be particularly acute where one party must take a first step that bears high costs before the other party must act. For example, a nation that has strong offensive military capabilities, but weak defensive systems, may be reluctant to refrain from positioning troops in a disputed territory and lose its tactical advantages without a firm guarantee that the other side will do the same. Without institutional mechanisms for enforcement, the first nation cannot be sure that the second nation will not exploit its own commitment to demilitarize in order to seize the disputed territory.
Nations should agree to a deal which reflects their chances of prevailing in a conflict, which depends on the balance of forces between the two sides. Each nation will have an expected value that it places on winning a dispute. The expected value of a war equals its expected benefit minus its expected cost. The expected benefit will be a nation’s probability of prevailing times the value of winning. The expected costs of the conflict will be the likely losses suffered from fighting. Before they launch a conflict, governments must estimate the probability of winning, the likely benefits from victory, and the costs of securing it. If both sides could know these things in advance, they should compromise accordingly. If one state is likely to win important benefits at a small cost, the potential opponent may see resistance as futile. If the attacker sees that conflict would entail large costs for no substantial gain, it does better by withdrawing or reducing its claims. In either case, war would be irrational.
Successful bargaining requires that nations act rationally. Leaders, however, may be delusional or motivated by incentives other than costs and benefits, such as a messianic religious vision. There will be less room to compromise with these regimes. They may hold little concern about the welfare of their people while giving much more attention to preserving their own hold on power. Such nations might still risk going to war, even though they have a low probability of winning and a high cost of casualties, because the odds are higher that the regime will remain in power. Compromise with authoritarian regimes will prove difficult, as with