From Charles Silver, A Private Law Defense of Zealous Representation, U. of Texas Law, Public Law Research Paper No. 638 (2020):
Moral philosophers object to the ethic of zeal, also known as the fiduciary duty and the principle of partisanship, because it requires lawyers to ignore any adverse effects that lawful actions beneficial for clients may have on third parties. For example, when representing a landlord, a lawyer may not refrain from evicting a tenant family that is behind on the rent for fear that the children will wind up on the street. Because harms inflicted on third parties normally bear on moral assessments, philosophers contend that lawyers who ignore them are amoral, immoral, or morally stunted.
Critics of zealous representation have won important battles. Where the Model Code of Professional Responsibility once canonized the requirement “to represent [a] client zealously within the bounds of the law,” the Model Rules of Professional Conduct now addresses zeal in a brief comment on diligence which emphasizes that a lawyer need not press for every advantage. Zealous representation has acquired a bad name.
This article offers a defense of zealous representation that is grounded in the common law of agency. The central points are, first, that the requirement to promote clients’ interests exclusively disciplines the common law by ensuring that principals’ rights and obligations are changed only with their consent; and, second, that the requirement facilitates the division and specialization of labor by shoring up principals’ confidence in agents who possess specialized knowledge and skills. Critics of the ethic of zeal have neither recognized these functions nor taken proper account of them when encouraging lawyers to give non-clients’ interests greater weight.
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The many lawyers and law professors who have written about the ethic of zeal bear more responsibility for the persistence of the debate than the philosophers who have criticized the profession from the outside. One cannot reasonably expect non-lawyers to have explored the ethic of zeal’s roots in agency law when lawyers and law professors, who should have known better, ignored them.
But philosophers do bear some responsibility for the widespread belief that a life spent helping people with legal problems cannot be fulfilling or morally justified. Scorn for lawyers comes through most clearly [by those] who accuse them of living in a simplified world, of refusing to grapple with moral dilemmas, or of being morally stunted. In fact, the fiduciary duty is the most morally demanding duty imposed by the common law. It requires lawyers to be altruistic. They must act solely for the benefit of clients, even to their own detriment if the need arises. Law is a helping profession, and the practice of law can be as worthwhile, fulfilling, and moral as any other line of endeavor which has the primary consequence of making people better off. It is by design, not by accident, that the virtues of agency—loyalty, obedience, diligence, and trustworthiness—are moral ones. To be a good lawyer, one must commit oneself to a code and be strong enough to do what the code requires, even when one would much rather do anything but.