Natural Property Rights is a work of normative theory. It focuses on what statutes and constitutional guarantees should say, not on what any current statutes or guarantees do say.

Imagine that a local government makes it illegal to emit more than a certain level of smoke in a specific area of town. Is such a law just? Prima facie, the law interferes with factory owners' freedom to produce useful products. If residents and clean businesses have land near the factory, though, the law protects their rights to use their lots for their own uses. If the anti-smoke ordinance is an anti-pollution ordinance, in a rights-based system it is a legitimate exercise of the police power—or a genuine "regulation."