It has always puzzled me why war itself is not declared a crime. Any party engaging in war should be declared a terrorist. /s
International law distinguishes between the legality of going to war, governed by "jus ad bellum," and the conduct within war, governed by "jus in bello" or international humanitarian law.
**Jus ad Bellum:**
- This set of rules determines under what conditions states may resort to war or use force. The United Nations Charter (1945) significantly restricts states' rights to wage war, primarily allowing it in self-defense or with a UN Security Council mandate.
- Under these principles, starting a war can be deemed illegal if it violates the UN Charter's provisions. However, the illegality of starting a war (aggression) is distinct from war crimes committed during a war.
**Jus in Bello (International Humanitarian Law):**
- Once war has begun, regardless of its legality, international humanitarian law applies to all parties equally. This law includes the Geneva Conventions and their Additional Protocols, aiming to protect those who are not participating in hostilities and to regulate the means and methods of warfare.
- War crimes are serious breaches of these laws, such as targeting civilians, using banned weapons, torture, and taking hostages. Committing war crimes is illegal and subject to prosecution, regardless of whether the war itself is legal.
**Aggression as a War Crime:**
- The Rome Statute of the International Criminal Court (ICC) has defined the crime of aggression, which includes planning, preparation, initiation, or execution of an act of using armed force by a State against the sovereignty, territorial integrity, or political independence of another state in a manner inconsistent with the United Nations Charter.
- While aggression is a leader's or country's act, war crimes can be committed by individuals and are prosecutable under international law.
**Defense Against War:**
- Defending against an aggressor is not a crime under international law. The right to self-defense is recognized under Article 51 of the UN Charter, provided the use of force is “necessary and proportionate.”
Contrary to many uninformed Hamas supporters, “proportionate” doesn’t mean since Hamas only killed 1400, then IDF can only kill 1400.
Proportionate looks at what is reasonably needed to repel the aggression. This means the response should be limited to what is required to address the threat. In this case the threat is Hamas leadership and Hamas terrorists — they can be pursued to be captured or killed to eliminate their threat.
It is legal for “Collateral Damage” in the form of civilian deaths. Efforts must be made to minimize harm to civilians and civilian infrastructure (such as is done with warnings and limited targeting) and a proportionate response considers the balance between the direct military advantage anticipated and the potential for incidental loss of civilian life or damage.
So war itself, especially to defend yourself, is not a crime under international law. Starting a war (such as Oct 7) is an act of aggression and thus illegal. Defending against war, when done in accordance with international law, is not a crime.