When does a state violate international law?

A state violates international law when it commits an “internationally wrongful act", which breaches an international obligation that the state was bound by at the time when the act took place.

International Law Commission’s Draft Article on  State Responsibility

One of the major legal instruments referred to in the context of state responsibility is the International Law Commission’s (ILC) Draft Articles on State Responsibility for Internationally Wrongful Acts.

The articles intend to complement existing obligations in other sources of international law such as the Four Geneva Conventions, and they provide a general supplementary framework for the concept of state responsibility.

They answer the questions - when does a state violate international law, and what is its responsibility if it does?

After five decades of revision and negotiation, the Draft Articles were finally adopted by the ILC in 2001, and later the same year, the UN General Assembly adopted a resolution which “commend(ed the articles) to the attention of Governments without prejudice to the question of their future adoption or other appropriate action”. Although they do not constitute a legally binding convention that states must follow, many of the principles correspond to existing international law.

The Draft Articles are followed by commentaries that provide a tool for their interpretation.

The International Law Commission is a body of independent legal experts, which operate under the General Assembly.

To UN and the ILC Draft Articles
To UN and the commentaries of the ILC Draft Articles
To the website of the International Law Commission 

Agreements must be respected

A State is bound to act in accordance with international customary law, and follow any international treaty it has signed and ratified. This is a fundamental principle in international law called “pacta sunt servanda” - agreements must be respected - which follows both from the Vienna Convention on the Law of Treaties, and international customary law. International humanitarian law (IHL) conventions and human rights treaties are examples of sources for a state’s international obligations.

Read more about treaty law and international customary law

To UN and the Vienna Convention on the Law of Treaties (458 kB)

Read more about international humanitarian law

Read more about human rights 

Exceptional cases - no state responsibility 

There are a number of exceptions when an act that normally would be a violation of international law, does not create responsibility of the state involved, such as cases of consent, self-defence or necessity (ILC Draft, Articles 20-26).

• Consent - Under certain sets of international law, it is possible for a state to consent to a violation of international law. A state may allow another state to use its air space or waters, and the invasion would not be considered an act of aggression.
• Necessity - If an act by a state (that may be considered illegal) was the only way for a state to safeguard an essential interest against a grave and imminent danger (and it does not damage another essential interest) - that state does not violate its international responsibilities.
• Self-defence - A state can not be held responsible if it acted in self-defence, as long as the act follows the UN Charter's rules on when the use of force can be used in self-defense (article 51 of the UN Charter).  

To UN Charter and Article 51

To the UN and the ILC Articles, where you can read more about the exceptions

In IHL and human rights

The exceptions mentioned above are less relevant when it comes to human rights and international humanitarian law (IHL).

A state cannot give its consent to another state to commit violations of human rights or IHL towards its citizens.

A state cannot claim that there is a necessity to prevent civilians of benefits they are entitled to in IHL, such as protection against targeted attacks.

A state cannot claim self-defence to justify violations of IHL and human rights.