  These questions are raised almost exclusively in contexts where there is already in place a functioning legal authority possessing coercive enforcement powers. The existence of such an ordering force has a significant effect on the ability of other agents in society to use and to detect specific uses of coercion, as well as other, non-coercive means of getting people to do things. When a generalized mechanism for ensuring compliance with law is in place, other entities − legal, corporate, and informal − can establish rules governing the use of various sanctions, disabilities, and rewards, and expect these to have certain effects. (For helpful discussion here, see Lucas 1966, 61.) For instance, merchants and customers engage in commerce, exchanging goods, because they are prevented from simply taking those goods by force, fraud, theft, etc. Sometimes the interactions between agents in a sub-legal context will overstep the boundaries between the voluntary and coercive, and thus render the actions of one party non-voluntary. But all such judgments here are made within a background context of laws that govern quite generally how persons may behave towards one another. And the coercive enforcement of those laws makes possible meaningful distinctions between coerced and uncoerced activity in all of the other parts of social life governed by the rule of law.