The correct answer is the willingness to come close to war.
Brinkmanship was an idea seen throughout the era of the Cold War. The increased political tensions between the United States and Soviet Union almost resulted in all out nuclear warfare several times. For example, during the Cuban Missile Crisis, the United States was mere minutes away from launching an attack on Soviet missiles in Cuba. This attack would have been met with fierece retaliation from the Soviets. However, both countries came to an agreement avoiding this type of warfare.