War is the use of organized violence to achieve political goals. Constraining this violence within a framework of rules is the aim of international law. Things become complicated, however, when this idea meets the messy reality in Israel and Gaza.

There is clarity about the brutal attack on October 7, when Hamas fighters entered Israel, killed more than 1,300 people and kidnapped almost 200 hostages. Stefan Talmon, a Germany-based international law expert, views this in the first instance as "mass murder." However, considering the long history between Israel and the Palestinians he also concludes: "Because of the scale and intensity of this attack on October 7, international law would consider that we are dealing with an armed conflict here."

Israeli Prime Minister Benjamin Netanyahu accordingly declared a state of war. The day after the massacre in southern Israel, Netanyahu said explicitly that Israel would lay to ruin every place where Hamas was operating or hiding. Since then, Israel has been bombing Gaza. Around 6,000 bombs were dropped on Gaza — an area equivalent in size to the city of Detroit — in just six days, with the bombing campaign continuing unabated. Over 4,000 people have been killed in Gaza, though the actual death toll there is likely much higher.

Four days after the attack, Israeli army spokesperson Daniel Hagari said that "hundreds of tons of bombs" had already been fired at Gaza, adding that "the emphasis is on damage and not on accuracy."

Self-defense — within limits

Israel's right to self-defense against armed attack according to Article 51 of the United Nations Charter is indisputable. This right, however, is restricted by international humanitarian law. Here, one of the most important principles is differentiation: The warring parties must differentiate between civilians and combatants, between civilian objects and military targets.

That only means, however, that civilians or civilian facilities are not allowed to be knowingly targeted in attacks. So, the killing of civilians is only forbidden when there is proof that it was done deliberately.

In practice, law professor Talmon explained, that means: "If Hamas positions a missile installation in a civilian neighborhood, Israel has the right to attack this missile installation — even at the expense of what is terribly called 'collateral damage' among the civilian population. And this collateral damage can, depending on the military goal and need, also be very high."

It is almost impossible to differentiate between civilian and military targets according to international law in the Gaza Strip, which has been under Israeli and Egyptian blockade since 2007 and is one of the most densely populated and built-up areas on Earth. Hamas tunnels run under apartment buildings; Hamas facilities are located in residential and office buildings. International law does not really account for this.

"If Hamas stays and hides in schools, mosques, hospitals, and operates command centers from there, then they become legitimate military targets," Stefan Talmon said. At the same time, it applies that: If Hamas sets up military positions in civilian areas, that counts as a war crime.

Collective punishment banned

Israel has imposed a total and comprehensive blockade on the Gaza Strip. Israeli Defense Minister Yoav Gallant spoke of a total siege, in which Gaza would be cut off from electricity, water, food and fuel supplies. Israeli human rights organization B'Tselem accuses Israel of war crimes, due to the extent of the airstrikes and the blockade. Humanitarian aid organization Doctors Without Borders speaks of a collective punishment of Gaza that contravenes international law.

According to Professor Talmon, most international law experts conclude that a total blockade – groceries, drinking water, fuel, medical products – is not in accord with international law. "In international law there is a ban on what is termed collective punishment, in this case the collective punishment of the entire Palestinian population of the Gaza Strip. Not all of them are members of Hamas and not all of them are responsible for this attack, but they are all being affected by this reaction from Israel just the same — indiscriminately."

Moreover, international law explicitly forbids starving out a civilian population. "If I impose a total blockade, at some point the food supplies or drinking water will run out, and then it comes to the point of starving out the civilian population. That is forbidden under international law," Talmon said.

Evacuation legal, expulsion illegal

On October 13, Israel's military told more than a million civilians in the northern part of the Gaza Strip —  almost half the total population — to move to the southern part of the area.

Because the infrastructure of the Gaza Strip is in ruins and there are not enough places for that many people to go to, the United Nations said such an evacuation was impossible. Jan Egeland, a former state secretary of Norway and current secretary general of the aid organization Norwegian Refugee Council, described the evacuation order as illegal. It is "not an evacuation opportunity, it's an order to relocate. Under humanitarian law, it's called forcible transfer of populations, and it's a war crime," he said.

In principle, however, Stefan Talmon explains, the evacuation of a civilian population by an occupying power is allowed under international law. "For example, to ensure the protection and safety of the population and enable military operations." According to Talmon's estimation, Israel is not acting unlawfully in this case.

"It would be against international law if Israel were to attempt to push out the population from the entire Gaza Strip. However, within the territory of an opponent, I can evacuate the population or force them to relocate for their own protection and security," the international law expert explained.

International law "is made by countries, for countries," Stefan Talmon said. Countries who thereby assume that they themselves will wage war one day. In doing so, they do not want to put shackles on themselves or impose rules which they then cannot follow." 
 
This article was originally written in German.