Physicians increasingly face conflicts between the ethic of undivided loyalty to patients and pressure to use clinical methods and judgment for social purposes and on behalf of third parties. The principal legal and ethical paradigms by which these conflicts are managed are inadequate, because they either deny or unsuccessfully finesse the reality of contradiction between fidelity to patients and society's other expectations of medicine. This reality needs to be more squarely acknowledged. The challenge for ethics and law is not to resolve this tension--an impossible task--but to mediate it in myriad clinical circumstances in a way that preserves the primacy of keeping faith with patients while conceding the legitimacy of society's other expectations of medicine.