STARTING IN THE 1960S, THE CONCEPT of coercion has received sustained attention from philosophers, resulting in a panoply of attempts to explain its nature and significance. Despite the apparent diversity in these efforts, the vast majority of them follow in a line of thinking laid out most influentially by Robert Nozick in 1969 which, roughly speaking, identifies coercion with the way one agent can put pressure on the will of another by means of threats. (1) This way of approaching the topic--I will call it the "pressure" approach--has come to seem wholly obvious to many subsequent writers, though it differs markedly from an earlier understanding of the nature of coercion that it largely supplanted. This earlier approach to coercion--which I will call the "enforcement" approach--regards coercion as a kind of activity by a powerful agent who creates and then utilizes a significant disparity in power over another in order to constrain or alter the latter's possibilities for action. This power differential may be used to put pressure on the coercee's will, but additionally it might work by simply interdicting or disabling agents, or disrupting various possibilities for action more systematically. Such systematic disruption can be achieved by incarceration or capital punishment, as well as via longstanding threats that alter broad patterns of activity, and not just specific actions. This approach sees differential power relations as essential to coercion so, on this approach, some ways in which agents put pressure on other agents that do not arise from significant power differentials will not register as coercion.
Choosing between the two approaches may depend on what questions one is trying to answer, and how the concept of coercion figures in them. Coercion is frequently thought to figure into determining a state's legitimacy and authority; it is also thought to be morally problematic, and so to be wrongful if not specially justified. Concern with coercion also arises due to its tendency to restrain human freedom and to curtail responsibility. Much of the recent work on coercion has been tailored to one or another of these issues, with a predominance of interest in the question of how coercion affects responsibility for actions taken under coercion. Whatever success has been achieved in tackling this question, it is now apparent that the pressure approach to coercion has encountered significant difficulty in explaining the social and political significance that has long been attributed to coercion. (2) Hence, part of the interest in elaborating and defending the enforcement approach, I will argue, is that it is more helpful than the pressure approach for assessing the social and political significance of coercion: whether or not one agent puts pressure on another's choice of actions, the use of the kind of power tracked by the enforcement approach is a matter of considerable social significance, and something that helps explain both the state's authority as well as its proper limits.
If the enforcement approach did just this much, it would then increase the range of theoretical treatments of the concept in a way that is useful for social and political philosophy. It would also bolster the view, held by theorists such as Alan Wertheimer and Mitchell Berman, that claims about coercion should be considered as applying only within a specific context, and that "the single unified conception of coercion that theorists seek ... is of little, if any, normative significance." (3) However that may be, I will argue that the enforcement approach is fundamental relative to the pressure approach in that its analysis of coercion accounts for the plausibility and usefulness of the pressure approach: insofar as the pressure approach is able to identify instances of coercion correctly, it is because it tacitly assumes that coercion works in the way the enforcement approach depicts explicitly. The commonsense view that coercion works by putting pressure on an agent's will thus spotlights an epiphenomenal aspect of coercion, rather than its most important explanatory aspects. …