Kevin Duffy explains libertarianism

The core principle of libertarianism is the non-aggression principle (NAP). The initiation of violence should not be tolerated. Proportional violence in self-defense, including protecting one’s property is permitted. Hiring agents (through peaceful, voluntary exchange) to defend one’s life, liberty and property is also consistent. 

Government, because it resorts to initiating violence, is inconsistent with NAP. This even applies to agents of self-defense (e.g., military, police, courts) because they are funded coercively. 

To the extent the left and right accept government intervention, they reject libertarian principles. They are two sides of the same interventionist coin and have much more in common than they realize. 

Libertarianism is value-agnostic and judges the morality of means employed. Every libertarian, of course, has their own unique set of values, as do all of us. I’m guessing nearly all believe moral means have the best chance of achieving those values. Interventionism, on the other hand, is ends-focused. The ends justify the means. Proponents believe their values have the best chance of being achieved through State coercion. 

Libertarians believe immoral means lead to trouble. Since most people are wired for intervention, any crisis is typically blamed on freedom (e.g. the free market, or capitalism) which brings about cries for even more intervention.

~ Kevin Duffy, "What are the basic principles of libertarianism?," Quora, December 17, 2020