This chapter summarizes the main lessons for diplomacy that we derive from our study. These eight lessons are: 1. A major factor separates the crises that escalate to war from those that do not; in the latter, a strong leader reins in any hard-liners who advocate going to war. 2. Individuals make a difference. 3. Contingency plays a more important role than system structure in determining whether or not a crisis escalates to war. 4. Someone must stand for peace. 5. The secret to preventing war structurally is to find a functional equivalent to war. 6. Norms and rules are important for avoiding war – and, therefore, maintaining peace. 7. War can be avoided; it is not inevitable. 8. The realist concepts of the national interest and balance of power do not always accurately describe the behavior of states.

Iceland and the United Kingdom experienced a series of crises that follow a similar pattern. Iceland extended its maritime limits – to preserve more fish for Icelandic vessels and conserve fish stocks. Britain resisted the extension. Both sides escalated their behavior (e.g., issuing threats and coercively harassing each another’s vessels), and Britain ultimately conceded. This chapter covers the 1971–1973 Cod War. It follows the above pattern, but with a somewhat unique twist. In the 1971–1973 episode, domestic politics within both democratic states encourage escalation. Iceland, moreover, threatens to leave the North Atlantic Treaty Organization (NATO) and to evict United States (US) forces from the Keflavik air base. Because of these threats, as well as escalating coercion, NATO mediates, and NATO and the US pressure Britain to concede. Ultimately, this crisis does not escalate to a major-state war because the disputed issue (i.e., maritime limits) lacks sufficient salience and past, similar episodes demonstrate that a nonwar solution exists.

The Russo-Japanese War features a failure of rational bargaining theory. Indeed, it shows how difficult it is for actors to successfully reach a mutually acceptable bargain, even when many of the conditions are favorable. An obvious quid pro quo existed during the crisis, and at one point the Russian ambassador, Rosen, and the Japanese representative actually agreed to it. Nevertheless, Alekseiev, the viceroy of the Russian Far East province – and later, the tsar himself – overruled Rosen. Although we identify several factors that contributed to this bargaining failure, domestic politics played a major role. Agreement occurred at a low(er) bureaucratic level; hard-liners in Russia, however, occupied the highest decision-making level(s) and overruled the obvious solution, thereby causing an unnecessary war. It is also worth noting that when Japan decided on war, it executed a surprise attack on Port Arthur. Because this attack succeeded, Japanese decision-makers learned it was effective and repeated the strategy in 1941 at Pearl Harbor.