"Second Strike" refers to a military strategy that ensures a country can respond to a nuclear attack with its own retaliatory strike. This concept is crucial for maintaining a balance of power, as it deters potential aggressors from launching a first strike, knowing they would face devastating consequences. The strategy relies on a country's ability to survive an initial attack and still launch a counterattack. This capability often involves a secure and diverse arsenal of nuclear weapons, including land-based missiles, submarines, and bombers, which are designed to remain operational even after an enemy strike.