The Articles on Responsibility of States for Internationally Wrongful Acts, known as ARSIWA, are a set of 59 provisions adopted by the International Law Commission in 2001 that spell out when a country has breached international law and what it must do about it. Although ARSIWA is not a treaty and no state has ratified it, international courts — including the International Court of Justice — routinely apply its provisions as an authoritative statement of customary international law on state responsibility. The framework answers four questions in sequence: whose conduct counts as the state’s, whether that conduct broke an obligation, whether any defense excuses the breach, and what the state owes once responsibility is fixed.
Why ARSIWA Carries Weight Without Being a Treaty
The UN General Assembly “took note” of the articles in Resolution 56/83 in December 2001 and annexed them, but it never opened them for signature as a convention. No country has ratified ARSIWA. Even so, the ICJ has cited the articles across multiple judgments when deciding whether a state acted wrongfully or owed reparation, and other tribunals treat them the same way. In practice, the articles function as the reference text on state responsibility, with the ILC’s detailed commentaries doing much of the interpretive work.
The Two-Part Test for a Wrongful Act
Article 1 states the core rule plainly: every internationally wrongful act by a state entails that state’s responsibility. Article 2 then breaks the test into two elements that must both be present. The conduct — whether an action or a failure to act — must be (a) attributable to the state under international law, and (b) constitute a breach of an international obligation the state owes.
Article 12 defines breach in functional terms. Conduct breaches an obligation when it fails to conform to what the obligation requires, and the source of the obligation does not matter. A duty grounded in a multilateral treaty, a bilateral agreement, or unwritten custom is analyzed the same way: compare the state’s conduct to the standard the rule sets, and any gap is a breach.
Whose Conduct Counts as the State’s
A state acts only through people, so the attribution rules decide which people’s conduct binds the state. This is where many disputes are actually won or lost.
State Organs and Delegated Authority
Article 4 provides the baseline. Anything done by a state organ counts as an act of that state, whether the organ is legislative, executive, or judicial, and whether it sits at the national or local level. A municipal police officer and a supreme court justice can each generate state responsibility.
Article 5 extends the rule to persons and entities that are not part of the formal government but are empowered by domestic law to exercise governmental authority. A private prison operator, a privatized border-screening company, or a security contractor performing statutorily delegated functions all fall into this category when acting in that authorized capacity. A state cannot outsource sovereign functions and shed accountability with them.
Direction, Control, and the Effective Control Test
Article 8 covers people or groups who act on the state’s instructions or under its direction or control. This is the rule that governs proxy-conflict situations: when does a government’s relationship with a militia, paramilitary group, or covert operative become close enough that the group’s conduct becomes the state’s own?
The leading standard comes from the ICJ’s 1986 judgment in Nicaragua v. United States. Even though the United States financed, trained, equipped, and generally oversaw the Nicaraguan contras, the Court held that was not enough to attribute the contras‘ specific battlefield conduct to the U.S. government. Attribution required proof of “effective control” over the particular operations during which the alleged violations occurred. The ICTY’s Appeals Chamber later proposed a looser “overall control” standard in Prosecutor v. Tadić, but the ILC sided with the ICJ when finalizing ARSIWA, and the ICJ has reaffirmed effective control in later cases.
Acknowledgment and Complicity
Article 11 captures a different scenario. If a state publicly endorses or adopts conduct that was not originally attributable to it — a government that celebrates an unauthorized embassy seizure and instructs the occupiers to continue, for example — the endorsement retroactively makes the conduct the state’s own. The rule prevents governments from quietly benefiting from rogue acts while disclaiming responsibility.
Article 16 addresses complicity between states. A state that knowingly aids or assists another state in committing a wrongful act bears its own responsibility, provided it knows the circumstances and the act would be wrongful if it had committed the act directly. Arms transfers and intelligence sharing during armed conflicts have made this provision increasingly consequential.
Defenses That Preclude Wrongfulness
Articles 20 through 25 list six circumstances in which conduct that would otherwise breach an obligation loses its wrongful character. None of them is invoked lightly, each carries strict conditions, and Article 26 draws a hard ceiling: none can excuse a violation of a peremptory norm of general international law, such as the prohibitions on genocide, torture, or aggression.
- Consent (Article 20). If the affected state validly consented in advance, the conduct is not wrongful to the extent it stays within the limits of that consent. A state that invites foreign troops in for a joint exercise cannot later call their presence a violation of sovereignty.
- Self-defense (Article 21). Conduct taken as a lawful measure of self-defense under the UN Charter is not wrongful. The act still has to satisfy the Charter’s requirements, including necessity and proportionality.
- Countermeasures (Article 22). An injured state may temporarily suspend its own obligations toward the responsible state to induce compliance, provided the measures meet the detailed conditions in Articles 49 through 54.
- Force majeure (Article 23). An irresistible force or unforeseen event beyond the state’s control that makes performance materially impossible can excuse non-compliance. The defense fails if the state caused the situation or assumed the risk of it.
- Distress (Article 24). When an official has no other reasonable way to save their own life or the lives of people in their care, the resulting breach is excused. It typically arises in maritime or aviation emergencies, and it does not apply if the state created the situation or the act would produce a comparable or greater danger.
- Necessity (Article 25). The narrowest defense. A state may invoke necessity only when the act is the sole way to safeguard an essential interest against a grave and imminent peril, and only if it does not seriously impair an essential interest of the other state or the international community. A state that contributed to the situation of necessity cannot rely on it. Investment tribunals have wrestled with necessity claims repeatedly, especially in disputes tied to economic crises.
One point often missed: even when one of these defenses applies, it does not erase any obligation to compensate for material loss caused by the conduct. A state that damages another’s property during a genuine emergency may still owe compensation, even though the act itself was not wrongful.
What the Responsible State Owes
Once responsibility is established, the responsible state faces immediate duties under Article 30: it must stop the wrongful conduct if it is still going on, and offer appropriate assurances and guarantees of non-repetition where circumstances call for them.
Beyond cessation, Article 34 requires full reparation, which can take three forms, alone or in combination.
- Restitution (Article 35). Restoring the situation that existed before the breach — returning seized territory, releasing detained individuals, revoking an unlawful measure. Restitution is the preferred remedy, but only when it is not materially impossible and would not impose a burden wildly disproportionate to the benefit compared with compensation.
- Compensation (Article 36). Monetary payment covering financially assessable damage that restitution does not cure, including lost profits where they can be established. This is the workhorse remedy, because most breaches cause economic harm that cannot simply be undone.
- Satisfaction (Article 37). For injuries that money cannot adequately address, the responsible state may owe an acknowledgment of the breach, an expression of regret, or a formal apology. Satisfaction cannot be disproportionate to the injury and must not humiliate the responsible state.
Serious Breaches of Peremptory Norms
Articles 40 and 41 create heightened consequences for the gravest violations. A “serious breach” under Article 40 is a gross or systematic failure to fulfill an obligation arising under a peremptory norm — the handful of rules so fundamental that no treaty or agreement can override them, such as the prohibitions on genocide, slavery, and aggression.
When such a breach occurs, Article 41 places two duties on every state in the international community. No state may recognize as lawful a situation created by the breach, and the duty reaches beyond formal diplomatic recognition to any act that would imply acceptance of the illegal situation. And no state may aid or assist in maintaining that situation. The classic examples involve territorial acquisitions achieved through force or the systematic denial of a people’s right to self-determination. These obligations run to all states, not only the directly injured party.
Countermeasures and Their Limits
Countermeasures are one of the few self-help tools available to an injured state in a legal system without centralized enforcement. Articles 49 through 54 permit a state that has been wronged to temporarily suspend some of its own obligations toward the responsible state, but only to pressure that state into complying with its duties of cessation and reparation. Countermeasures are not punishment.
The restrictions are substantial. Countermeasures must be proportionate to the injury, taking the gravity of the breach into account. They must be reversible, so the suspended obligations can resume once the responsible state complies. Certain obligations can never be targeted at all: the prohibition on the use of force, fundamental human rights protections, humanitarian law obligations prohibiting reprisals, other peremptory norms, and the inviolability of diplomatic and consular personnel and premises.
Procedurally, the injured state must first call on the responsible state to fulfill its obligations and notify it of any decision to take countermeasures, offering to negotiate. Urgent measures needed to preserve the injured state’s rights are an exception. If the responsible state complies, or if a binding dispute-resolution process is being pursued in good faith, countermeasures must be suspended or ended.
Who Can Bring a Claim
Not every state can bring every claim. ARSIWA distinguishes between the injured state and other states with a legal interest in compliance.
Article 42 defines the injured state as the one to which the breached obligation was owed individually, or which is specially affected by a breach of a collective obligation. An injured state invokes responsibility by notifying the responsible state of its claim and specifying what conduct should stop and what reparation it seeks.
Article 48 opens the door for states that are not directly injured. Where an obligation is owed to a group of states to protect a collective interest, or to the international community as a whole, any state in the group — or any state at all, for community-wide obligations — may demand cessation and reparation on behalf of the injured parties. This provision gives standing to challenge violations of fundamental norms even where the complaining state suffered no direct economic or physical harm, moving beyond the traditional bilateral model of international disputes.
Article 44 imposes two admissibility conditions. The claim must satisfy any applicable rule on nationality of claims, since a state generally cannot champion someone who is not its national. And where applicable, the injured individual or entity must have exhausted all available and effective local remedies in the responsible state’s legal system before the claim moves to the international level. These requirements give the responsible state a chance to address the wrong at home before it becomes a matter between sovereigns.