Coverage of the war between Israel and Hamas has been peppered with references to international law, international humanitarian law, war crimes, proportionality and the Geneva Conventions, which underpin large sections of international humanitarian law.
The following is an explanation of each of those terms and their signficance to the Israel-Hamas war.
International law
Broadly understood, international law is the collection of agreements between and among the nations of the world that govern how they interact with one another. There is no single compendium of documents that establishes a discrete body of legislation known as "international law," but the concept is widely understood and accepted by most countries in the world.
In its charter, the United Nations is given the task of "promoting international co-operation in the political field and encouraging the progressive development of international law and its codification."
According to the U.N., "The international law is enshrined in conventions, treaties and standards. Many of the treaties brought about by the United Nations form the basis of the law that governs relations among nations."
Since its founding, the U.N. has been the repository of more than 500 multilateral treaties that form much of the basis for what is today considered "international law."
International humanitarian law
Also known as the law of armed conflict, international humanitarian law is a subset of international law specifically concerned with how wars and other armed conflicts are conducted.
According to the International Committee of the Red Cross, "International humanitarian law is a set of rules which seek, for humanitarian reasons, to limit the effects of armed conflict. It protects persons who are not or are no longer participating in the hostilities and restricts the means and methods of warfare. International humanitarian law is also known as the law of war or the law of armed conflict."
Importantly, international humanitarian law is not concerned with the question of whether a country is justified in going to war, but only with the conduct of hostilities once they commence.
Fionnuala Ni Aolain, a regents professor at the University of Minnesota and a former U.N. special rapporteur on counterterrorism, told VOA that laws governing the conduct of war are among the oldest of all treaties and norms of international law.
"Wars have rules," she said. "They've had rules for a really long time."
While much of the law of armed conflict is determined by treaties, other elements are not codified. State and nonstate actors are considered bound by certain elements of international humanitarian law, even if they have not officially accepted it themselves.
"Some parts of the law of war are not in treaties but have been established through the practice of states — meaning it's something that states consistently do without having actually written it down," Ni Aolain said. "The reason why that's important is because to be bound by a treaty, you have to have signed the treaty. But customary international law binds without having signed it."
Ni Aolain also said that once a nation is engaged in armed conflict, all the rules of international humanitarian law apply, and the obligation to observe them is not contingent on the behavior of an opponent.
For example, international humanitarian law specifically bars the use of terrorism. However, she said, the fact that an adversary has resorted to terroristic tactics in an armed conflict does not absolve other parties to the conflict of the obligation to observe the law.
Geneva Conventions
The best-known elements of international humanitarian law are the Geneva Conventions, a set of multilateral treaties laying out the obligations governments engaged in armed conflict have toward noncombatants.
Though their history stretches back into the 1800s, when people refer to the Geneva Conventions today, they generally mean four treaties signed by dozens of countries in 1949, along with three additional protocols negotiated in later decades.
The four original conventions relate to the treatment of the sick and wounded in war on land; the treatment of sick, wounded and shipwrecked sailors in war at sea; the treatment of prisoners of war; and the protection of civilians during times of war.
Currently 196 countries, including all member states of the U.N. as well as the State of Palestine, which has observer status with the U.N., are signatories of the four original conventions.
New protocols
In 1977, many nations agreed to adopt what are now known as Protocol I and Protocol II of the Geneva Conventions.
Protocol I reaffirms the contents of the original conventions and states that in the context of international conflicts, their protections extend to "armed conflicts in which peoples are fighting against colonial domination and alien occupation and against racist regimes in the exercise of their right of self-determination."
Protocol II is meant to clarify the extent to which the conventions apply to conflicts that are not international in nature, in that they take place within the borders of a sovereign state.
Several countries that are party to the four original conventions declined to sign on to Protocols I and II, including Israel. The United States signed both, but never ratified them, meaning the U.S. government does not recognize them as legally binding.
War crimes
Aisling Reidy, a senior legal adviser with Human Rights Watch, told VOA that a war crime consists of "a serious violation of international humanitarian law, for which someone bears individual criminal responsibility."
Including what are known as "grave breaches" of the Geneva Conventions, some actions considered war crimes are targeted killings of civilians, rape and the taking of hostages.
Reidy said there are also some violations of the laws of armed conflict that don't rise to the level of war crimes. Importantly, she said, demonstrating that an act was undertaken with criminal intent is an essential element in proving that a war crime has been committed.
One authoritative description of what most of the international community considers to be war crimes is compiled in Article 8 of the Rome Statute of the International Criminal Court (ICC).
Neither Israel nor the United States is a signatory of the Rome Statute or recognizes the authority of the ICC, in part because Article 8 codifies elements of Protocols I and II of the Geneva Conventions, which neither party has ratified.
Proportionality
The concept of proportionality in warfare is frequently a source of confusion. While it may sound as though it refers to something broader, for purposes of the laws of armed conflict, proportionality refers to the methods involved in a specific attack and their collateral consequences.
Specifically, the law requires that in mounting an attack on a military target that may also result in injuries to noncombatants or damage to civilian property, the amount of force used must be commensurate with the importance of the objective the attack is intended to achieve. The requirement that the force used be proportionate to the objective does not specifically outlaw attacks that can be expected to result in collateral damage to civilians or civilian property.
The Rome Statute, for example, defines the following as a war crime: "Intentionally launching an attack in the knowledge that such attack will cause incidental loss of life or injury to civilians or damage to civilian objects or widespread, long-term and severe damage to the natural environment which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated."