The realist dismissal of international law remains seductively simple: states obey legal rules only when convenient, great powers write rules that serve their interests, and enforcement mechanisms are too weak to matter. This skepticism has shaped generations of foreign policy practitioners who view international law as either naive idealism or sophisticated cover for power projection. Yet this framework systematically fails to explain some of the most consequential developments in international relations.

Consider how human rights norms have constrained even powerful states in ways their architects never intended. Or how smaller states consistently invoke legal frameworks to extract concessions from stronger adversaries. The realist cannot adequately explain why states invest enormous diplomatic capital in legal institutions that supposedly lack binding force, or why violations provoke genuine reputational costs rather than mere rhetorical condemnation.

The inadequacy of pure power analysis becomes clearer when we examine how international law actually functions rather than measuring it against domestic legal systems it was never designed to replicate. What emerges is a more sophisticated understanding of law's role in international politics—not as a constraint external to power, but as a framework that shapes what power means and how states understand their own interests.

The standard realist critique begins with enforcement: domestic law works because police and courts compel compliance, while international law lacks equivalent mechanisms. Without a global sovereign wielding legitimate coercion, international agreements remain mere promises states break whenever costs exceed benefits. This argument seems devastating but rests on a fundamental misunderstanding of how even domestic compliance actually works.

Most domestic legal compliance occurs without any enforcement intervention whatsoever. Citizens pay taxes, honor contracts, and respect property rights primarily through internalized norms and reputational concerns rather than fear of police action. The enforcement apparatus matters not because it directly compels most behavior, but because it reinforces expectations about what constitutes legitimate conduct. International law operates through analogous mechanisms adapted to a decentralized system.

States comply with international obligations primarily through reciprocity, reputation, and internalization. Reciprocity creates iterated game dynamics where violation invites retaliation across multiple issue areas. A state that breaks trade commitments finds partners less willing to negotiate security arrangements. Reputation effects extend beyond immediate counterparties—third-party observers update beliefs about a state's reliability as a partner in all future interactions.

Internalization operates through domestic legal incorporation and bureaucratic routine. Once international commitments become embedded in domestic legislation, regulatory procedures, and professional training, compliance becomes the path of least resistance regardless of external monitoring. Military lawyers trained in laws of armed conflict shape operational decisions in ways that persist even when violation would go undetected.

The decentralized enforcement mechanisms available internationally—countermeasures, dispute resolution, conditional cooperation, naming and shaming—prove more effective than realists acknowledge precisely because they leverage these compliance pulls rather than attempting to replicate domestic coercion. International law works differently than domestic law, but difference does not equal dysfunction.

Takeaway

Compliance with law—domestic or international—depends primarily on legitimacy, reciprocity, and institutional embedding rather than coercive enforcement. Evaluate international legal effectiveness by how it shapes expectations and routines, not by counting enforcement actions.

Realism treats state interests as formed prior to and independent of legal frameworks—states know what they want, then use law instrumentally to achieve predetermined goals. This picture fundamentally misunderstands how legal categories shape the very possibilities states can conceive. International law does not merely regulate pre-existing actors pursuing pre-existing interests; it constitutes those actors and interests in the first place.

The concept of sovereignty itself exemplifies law's constitutive function. Sovereignty is not a natural fact discovered by political scientists but a legal construct that creates certain entities (states) as the legitimate holders of certain powers (territorial jurisdiction, treaty-making capacity, immunity from foreign courts). Without the legal framework of sovereignty, the interests we attribute to states—territorial integrity, non-interference, diplomatic recognition—would be literally inconceivable.

Consider how international environmental law has transformed state interests regarding atmospheric emissions. Before climate regimes created categories like emissions allowances, carbon budgets, and nationally determined contributions, states could not conceptualize their interests in these terms. The legal framework did not constrain pre-existing preferences about carbon policy; it created the cognitive categories through which such preferences could be formed and expressed.

Human rights law similarly constitutes new interests by establishing individuals as subjects of international concern. Once legal instruments recognize human rights as legitimate international matters, states develop interests in their own human rights performance and others' human rights practices that simply did not exist before this legal construction. Governments create human rights bureaucracies, civil society develops monitoring capacity, and foreign policy incorporates human rights considerations—all because legal frameworks made these categories thinkable.

This constructivist insight reveals why reducing law to power misses something essential. Power itself requires legal categories to become meaningful in international relations. Military capability translates into influence partly through legal frameworks governing use of force. Economic strength operates through trade law, investment protection, and monetary arrangements. Law does not constrain power from outside; it constitutes the very channels through which power flows.

Takeaway

Legal frameworks do not simply constrain what states can do—they create the categories through which states understand what they are and what they want. When analyzing international politics, ask not just how law limits power, but how it constitutes power's meaning.

If international law merely reflected power distribution, we would expect legal innovations to originate from great powers and spread through coercive imposition. The historical record reveals a strikingly different pattern. Many of the most transformative international legal developments emerged from unlikely sources and spread through mechanisms that cannot be reduced to material power differentials.

The anti-apartheid sanctions regime illustrates this dynamic. Small African states with negligible material capabilities successfully mobilized international legal condemnation against a state supported by major Western powers. The normative cascade that made apartheid internationally illegitimate proceeded through moral argumentation, coalition-building among weak states, and gradual shifting of legitimacy standards—not through power projection by the movement's initial supporters.

Similarly, the landmine ban emerged primarily through civil society advocacy and smaller states' diplomatic entrepreneurship, ultimately constraining great powers including the United States despite Washington's initial opposition. The legal norm spread through moral persuasion, expert networks, and domestic political pressure rather than material incentives or coercive threats. Once a critical mass of states adopted the norm, remaining outside became increasingly costly to legitimacy regardless of military capability.

The responsibility to protect doctrine shows normative innovation spreading through argumentative processes among states, international organizations, and transnational advocates. Its emergence reflected changing understandings of sovereignty and human rights rather than shifts in power distribution. That powerful states subsequently invoked R2P selectively does not negate that the framework itself emerged through normative rather than power-based dynamics.

These cascades follow predictable patterns: norm entrepreneurs identify problems, frame them in compelling moral terms, build coalitions starting with sympathetic states, gradually shift what counts as legitimate behavior, and eventually reach tipping points after which holdouts face serious reputational costs. This process operates through the logic of appropriateness rather than purely through the logic of consequences. States come to comply because they accept the norm's legitimacy, not merely because they calculate compliance serves material interests.

Takeaway

Legal innovations often emerge from unlikely sources and spread through moral persuasion, coalition-building, and shifting legitimacy standards rather than power imposition. Watch how normative entrepreneurs frame issues and build coalitions—these processes can reshape international order in ways pure power analysis cannot predict.

Recognizing international law's genuine force does not require naive idealism about its consistent application or pretending that power plays no role in legal outcomes. Great powers do shape legal frameworks, interpret obligations self-servingly, and sometimes violate rules with impunity. But this familiar reality coexists with law's deeper functions—creating the categories through which international politics becomes intelligible, establishing legitimacy standards that constrain even the powerful over time, and enabling transformative change through mechanisms irreducible to material capability.

The sophisticated analyst neither dismisses international law as epiphenomenal nor treats it as automatically effective. Instead, they investigate how legal frameworks interact with power, identity, and interest in specific contexts. They trace how legal arguments gain or lose persuasive force, how compliance mechanisms succeed or fail, and how normative innovations spread through international society.

This approach proves essential for addressing contemporary global challenges. Climate change, artificial intelligence governance, pandemic preparedness—none of these problems can be managed through power politics alone. Understanding how international law actually works, rather than dismissing it through outdated realist frameworks, becomes not merely an academic exercise but a practical necessity for navigating an increasingly complex world.