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Why does law claim the right to direct our conduct, and when, if ever, does that claim succeed? The question of legal obligation sits at the heart of jurisprudence. Every legal system tells its subjects that they must act in certain ways, but the source and limits of that "must" have been contested for more than two millennia. The history of this subfield is not a steady accumulation of answers but a series of competing frameworks, each redefining what an adequate account of obligation requires.
The oldest surviving framework, Natural Law Theory, grounds legal obligation in the moral order of the universe. For thinkers from Aristotle to Thomas Aquinas to John Finnis, a rule that is radically unjust is not truly law and therefore cannot obligate. The obligation to obey law is derivative of the obligation to do good and avoid evil. This framework treats the question of obligation as inseparable from the question of law's moral content: an unjust law is not binding in conscience, though it may still be enforced by coercion.
Social Contract Theory, which flourished from the seventeenth to the eighteenth centuries, offered a fundamentally different basis. Where Natural Law Theory looked to cosmic morality, contract theorists such as Thomas Hobbes, John Locke, and Jean-Jacques Rousseau grounded obligation in the consent of the governed. On this view, legal obligation arises because individuals have agreed—explicitly or tacitly—to surrender some freedom in exchange for the benefits of political order. The two frameworks coexisted for a time, but they disagreed sharply: Natural Law Theory made obligation depend on the content of the law, while Social Contract Theory made it depend on the act of agreement. Both, however, shared the assumption that obligation requires a moral foundation, whether cosmic or consensual.
Legal Positivism, emerging in the early nineteenth century with Jeremy Bentham and John Austin, broke decisively with both traditions. Positivists argued that legal obligation is a matter of social fact, not moral merit. Austin defined law as the command of a sovereign backed by threats; obligation, on this picture, was simply the probability of suffering a sanction for disobedience. H. L. A. Hart later transformed positivism by replacing commands with rules. In The Concept of Law (1961), Hart distinguished being obliged (forced by threat) from having an obligation (being guided by an accepted rule). For Hart, legal obligation arises from the union of primary rules of conduct and secondary rules of recognition, change, and adjudication. The key point of disagreement with Natural Law Theory was sharp: a law could be legally valid and legally obligatory even if it was morally abhorrent.
Analytical Jurisprudence, which emerged around 1900, provided the methodological backbone for positivism and for much of twentieth-century legal philosophy. Its practitioners—including Hart, Hans Kelsen, and later Joseph Raz—insisted that the first task of jurisprudence is to clarify the concepts used in legal thought: What is a rule? What is a right? What is a duty? Analytical Jurisprudence did not itself take a substantive position on the ground of obligation, but it supplied the tools that positivists used to build their accounts. It also became the method that later critics, including interpretivists and critical theorists, would adopt or challenge.
In the 1950s and 1960s, the Legal Process School offered a different picture. Developed by Henry Hart and Albert Sacks at Harvard, this framework located obligation not in morality, consent, social facts, or commands, but in the institutional processes by which law is made and applied. For the Legal Process School, law is a purposive enterprise, and the obligation to obey a legal directive depends on whether it was produced by the right institution using the right procedures. This approach narrowed the question of obligation: instead of asking what makes law binding in general, it asked which institutions are entitled to make which decisions. The Legal Process School declined after the 1970s, partly because its faith in institutional regularity seemed naive in an era of political polarization. But its procedural legacy persists in administrative law and constitutional doctrine, where the legitimacy of official action often turns on whether proper procedures were followed.
Interpretivism, associated primarily with Ronald Dworkin, mounted a direct challenge to Legal Positivism. Dworkin argued that law cannot be identified without moral judgment. In a hard case, judges must decide what the law requires by interpreting legal materials in the light of principles of political morality that best justify the community's legal practices. For Dworkin, legal obligation is not a matter of social facts alone; it is an interpretive concept. A judge deciding whether a statute applies to a novel situation must ask which interpretation makes the law the best it can be, morally speaking. This directly clashed with positivism's core claim that law can be identified without recourse to morality. Interpretivism preserved the idea that obligation is a normative concept, but it rejected the positivist separation of law and morality.
Joseph Raz's Service Conception of Authority, developed from the 1970s onward, attempted to mediate between positivism and interpretivism. Raz argued that law claims legitimate authority, and that authority is justified only if it helps subjects act better on the reasons that already apply to them (the "normal justification thesis"). On this view, legal obligation is not a brute social fact, but it is also not a matter of moral interpretation in Dworkin's sense. Instead, law's authority is parasitic on the reasons subjects have independently. The Service Conception preserved positivism's insistence that law's existence is a social fact, but it gave a moral account of when that law actually obligates. This made it a hybrid: it agreed with interpretivism that obligation has a moral dimension, but it agreed with positivism that law can be identified without moral judgment.
Beginning in the 1970s, a wave of critical frameworks challenged the very terms of the obligation debate. Critical Legal Studies (CLS) argued that law is radically indeterminate: legal materials do not dictate unique outcomes, so the claim that law obligates is often a mask for political power. For CLS, the question of obligation is not about moral or social foundations but about ideology. Law obligates not because it is justified but because it is hegemonic. This framework rejected the assumption shared by positivists and interpretivists alike that law has a determinate content that can ground obligation.
Feminist Legal Theory, emerging at roughly the same time, argued that mainstream accounts of obligation ignore the ways law has been shaped by patriarchy. Feminist theorists such as Catharine MacKinnon and Robin West asked: Whose consent counts in Social Contract Theory? Whose interpretation is authoritative in Dworkin's scheme? Whose social facts are recognized in Hart's rule of recognition? For feminist theory, legal obligation is not a neutral concept; it is a site of gendered power. The obligation to obey law may be experienced differently by those whom the legal system has historically excluded or subordinated.
Critical Race Theory (CRT), which developed in the 1980s, extended this line of critique to race. Scholars such as Derrick Bell and Kimberlé Crenshaw argued that law's claim to obligation is undermined by its complicity in racial hierarchy. For CRT, the question is not whether law can obligate in the abstract, but whether a legal system built on racial subordination can claim the allegiance of those it oppresses. This framework did not reject the concept of obligation outright, but it insisted that any adequate account must confront the history of racism.
All three critical frameworks shared a suspicion of the mainstream debate. They agreed that positivism, interpretivism, and the Service Conception all abstract away from power, but they disagreed among themselves about which form of power—class, gender, or race—is most fundamental. They remain active traditions, each continuing to refine its critique and to propose alternative accounts of how law binds its subjects.
Legal Pluralism, also emerging in the 1970s, challenged a different assumption: that legal obligation comes from a single, unified legal system. Legal pluralists such as Sally Engle Merry and Franz von Benda-Beckmann argued that in any society, multiple normative orders—state law, customary law, religious law, community norms—coexist and compete. For legal pluralism, the question "Why obey the law?" is misleading because it assumes a single source of obligation. In practice, individuals navigate overlapping obligations, and the state's claim to supremacy is often contested. This framework coexists uneasily with both positivism and interpretivism, which tend to assume a unified legal system. It has been especially influential in postcolonial and transnational contexts.
Today, no single framework commands universal assent. Legal Positivism, especially in the form developed by Hart and refined by Raz, remains the dominant approach in Anglophone jurisprudence. Most legal philosophers accept that law's existence is a matter of social fact, even if they disagree about the implications for obligation. Interpretivism remains a major alternative, particularly in constitutional theory and in jurisdictions where courts play a strong role in shaping legal meaning. The Service Conception of Authority is widely discussed but also widely criticized; it has not displaced either positivism or interpretivism.
Natural Law Theory continues to have advocates, especially in Catholic and Thomist traditions, but it is a minority position in secular legal philosophy. Critical Legal Studies has declined as an organized movement, but its insights about indeterminacy and ideology have been absorbed into other critical frameworks. Feminist Legal Theory and Critical Race Theory are now established subfields with their own journals, conferences, and debates. They do not offer a single unified account of obligation, but they have permanently changed the terms of the discussion: it is no longer possible to write about legal obligation without addressing power, exclusion, and identity.
Legal Pluralism has grown in importance as globalization and transnational law have made the boundaries of legal systems less clear. It is now a standard framework in legal anthropology and sociolegal studies, though it remains somewhat marginal in mainstream analytical jurisprudence.
What do the leading frameworks agree on? Most accept that legal obligation is a normative concept—it is about what people ought to do, not just what they are forced to do. Most also accept that law claims authority, even if they disagree about whether that claim is ever justified. The deep disagreement is about the relationship between law and morality. Positivists hold that law can be identified without moral judgment; interpretivists and natural lawyers deny this. Critical theorists add that the very terms of this debate obscure the role of power. The question of legal obligation remains open, and each framework continues to press its case, refine its arguments, and respond to its rivals.