I do not generally subscribe to a natural rights theory of humanity, but the "presumption of liberty" is still a sufficient guideline for most of the examples given that policing powers should be restricted to areas of significant importance because of the actual damage they could maintain. Basic health, safety, fraud, and environmental regulations all can fall into these categories, and likewise we should avoid regulations and laws providing power to governments in areas that are effectively arbitrary, narrowly beneficial/prejudicial (rent seeking or targets of oppression), or, and this is a big objection for me usually, ineffective at achieving the presumed ends.
All of that generally means that if governments want to pass some rule, at any level of governance, it needs to pass two basic tests for me to find it beneficial to have a rule rather than the absence.
1) What goal is this law seeking to achieve, and is that goal a necessary end of the state to police (or can it be done in some other way)? In some cases, I will part from ordinary libertarians on questions of social welfare or social justice because I am not persuaded there are good options available in the society at large for resolving these questions and a large free rider or externality problem. In many cases of legal questions, this differs from the ordinary interpretation (by liberals and conservatives) to say that the idea that we need a law to do X is possibly an illegitimate aim for the state to impose controls over. My guiding assumption is to say that if there isn't a rule saying the government can't do it that isn't a license to say governments can or should do it, and that it needs a very good reason to intercede. This used to be a fairly uncontroversial assumption for how the American government operated from what I could tell that if it wanted to do something limiting individual rights severely, it needed a constitutional amendment (eg, the 18th). Indeed, it seems to have been a basis for passing the 14th amendment in the first place as a fairly radical amendment limiting the scope of government to the protection and guarantee of existing rights such as the freedom of conscience or speech or the protection against unreasonable searches by government agents, and the enforcement of generally applicable laws (eg, murder, theft, fraud, rape, etc). This is no longer the dominant theory governing American politics and the power of the 14th amendment is often much more limited in restraining political (and commercial) authority from doing unreasonable things.
2) Does the proposed rule/law have a good mechanic for achieving that goal? This is typically a big problem. I often see very little evidence that a proposed law will work, or may even be counterproductive, or that it has even much to do with achieving a purported goal and is instead about something else (such as rent seeking behavior in public choice theory).
The danger of Barnett's theory is that courts do not always subscribe to a protection of liberty in the first place and that courts have often expanded radically the scope of government operations to allow things that not only libertarians but many others may find to be illegitimate, ineffective, or inappropriate operations of government. Courts do not have to abide by a limited interpretation of governmental power (at any level) or can choose to defer to legislatures or executives in both the intended premise and the intended execution of a law.
Linky Friday: The Scientific Darkness
1 hour ago