Final answer:
Deadly force is authorized under circumstances of Imminent Threat, Self-Defense, Defense of Others, and in some cases, Protection of Property, focusing on the safety of life and sometimes assets. It aligns with libertarian principles of Defensive and Retaliatory force to uphold individual rights and justice. These principles are also reflected at the macro level in maintaining National Security against various threats.
Step-by-step explanation:
Deadly force is normally authorized in a number of specific circumstances which revolve around the preservation of life and property. Imminent Threat, Self-Defense, and Defense of Others are three primary scenarios. In these situations, the use of deadly force is considered justified to protect oneself or others from a perceived threat that could result in serious bodily harm or death. Additionally, while less common, Protection of Property can sometimes warrant deadly force, specifically in scenarios where there's a belief that the property's unlawful seizure will also pose an immediate threat to life or safety.
Libertarians propose that while the initial use of force is opposed, the use of Defensive force is appropriate when one's rights are threatened, such as for self-defense. Furthermore, the government should act to protect individuals through the use of defensive force. Similarly, Retaliatory force may be used as a just retribution against those who initiated force, and it's upheld by judicial systems to penalize the aggressors.
In terms of national security, the concept extends to protecting a nation's citizens, economy, and allies. The range of threats that might necessitate the use of force include military threats, economic threats, as well as non-state actors. National security now requires economic, energy, environmental security, and a strong military capability to counter various types of threats.