Do citizens of a nation such as the United States have a moral duty to obey the law? Do officials, when interpreting the Constitution, have an obligation to follow what that text meant when ratified? To follow precedent? To follow what the Supreme Court today says the Constitution means?

These are questions of political obligation (for citizens) and interpretive obligation (for anyone interpreting the Constitution, often officials). Abner Greene argues that such obligations do not exist. Although citizens should obey some laws entirely, and other laws in some instances, no one has put forth a successful argument that citizens should obey all laws all the time. Greene’s case is not only “against” obligation. It is also “for” an approach he calls “permeable sovereignty”: all of our norms are on equal footing with the state’s laws. Accordingly, the state should accommodate religious, philosophical, family, or tribal norms whenever possible.

Greene shows that questions of interpretive obligation share many qualities with those of political obligation. In rejecting the view that constitutional interpreters must follow either prior or higher sources of constitutional meaning, Greene confronts and turns aside arguments similar to those offered for a moral duty of citizens to obey the law.

Laws and regulations are ubiquitous, touching on many aspects of individual and corporate behavior. But under what conditions are laws and rules actually effective? A huge amount of recent work in political science, sociology, economics, criminology, law, and psychology, among other disciplines, deals with this question. But these fields rarely inform one another, leaving the state of research disjointed and disorganized. Lawrence M. Friedman finds order in this cacophony. Impact gathers recent findings into one overarching analysis and lays the groundwork for a cohesive body of work in what Friedman labels “impact studies.”

The first important factor that has a bearing on impact is communication. A rule or law has no effect if it never reaches its intended audience. The public’s fund of legal knowledge, the clarity of the law, and the presence of information brokers all influence the flow of information from lawmakers to citizens. After a law is communicated, subjects sometimes comply, sometimes resist, and sometimes adjust or evade. Three clusters of motives help shape which reaction will prevail: first, rewards and punishments; second, peer group influences; and third, issues of conscience, legitimacy, and morality. When all of these factors move in the same direction, law can have a powerful impact; when they conflict, the outcome is sometimes unpredictable.