The plumbline libertarian ethic is the rational natural-rights ethic elaborated by Murray Rothbard in The Ethics of Liberty. The fundamental principles of the natural-rights ethic are self-ownership and original appropriation (homesteading). These principles are universal and absolute and true. Any violation of these principles is a crime. Thus, a crime is aggression against a person or justly acquired property. Consequently, libertarians are plumbline advocates of the non-aggression principle (NAP).
Further blog posts will apply the principles of the libertarian natural-rights ethic to medicine (libertarian bioethics).