  Wertheimer's approach is developed and defended by surveying legal reasoning in the U.S. and its common-law tradition with respect to such matters as contracts, criminal responsibility, plea bargains, blackmail, and consent to searches and medical procedures. His work has been influential among many who have tried to determine what the law should say about various coercive phenomena, and Wertheimer himself has offered further applications of his theories in subsequent work, including a book on consent to sexual relations (Wertheimer 2004). Wertheimer's moralized account and moralized theories of coercion more generally raise some difficulties for understanding how there could be “justified coercion,” such as law enforcement, in that they tend to associate uses of coercion with immoral action. Some of these difficulties are considered in Section 3.4 below.