Last year, I was invited to join other Princeton University academics in viewing a compilation of raw footage from GoPro cameras carried by Hamas gunmen killing civilians in Israel on Oct. 7. Additional video and audio material came from dashboard cameras, traffic cameras, phone intercepts and victims’ phones.

The invitation carried a warning that the footage would show horrific violence and murder. I avoid violent movies, so my instinctive response was to decline the invitation. But as someone who often points to the progress that we have made, over millennia, in expanding the circle of moral concern, I decided that I should be willing to see something that would challenge my optimism.

Evil is a word I rarely use, but what I saw was evil in its purest form: men armed with assault rifles going house to house to shoot defenseless and terrified families in their simple kibbutz homes, recording their murders and shouting “God is Great.” They kill a father in front of his two young children. They cut off the head of one of their victims, saying they will give it to the crowd to play with. We see panicked young people at a music festival shot dead as they try to hide or flee. I was seeing only a fraction of the 1,200 murders Hamas forces committed on that day, according to official Israeli figures.

Be’eri, a kibbutz near Gaza, was built on socialist principles and, despite Israel’s marked swing to the right, retained its left-wing values. Members were opposed to Israel’s current right-wing government and believed that peace with the Palestinians was still possible. Kibbutz members had helped transport people from Gaza to and from medical treatment in Israel. But to Hamas, that made no difference. At Be’eri, the gunmen murdered 97 people.

When the Israeli military first showed this footage to journalists, Adm. Daniel Hagari, the chief military spokesperson, said: “We want to understand ourselves why we are in a war and what we are fighting for.” At that time, Oct. 23, the death toll in Gaza, according to the Hamas-run Health Ministry, had just surpassed 5,000.

Seeing the video did help me to understand why Israel is prepared to accept the deaths of so many Palestinians. Watching such callous killings, I found it impossible to resist the feeling that the killers themselves should be killed. To feel this is not in itself wrong: to choose to act on it, however, usually is, for it makes a bad situation worse. By the time I saw the footage, Hamas was saying that Israel’s attacks had killed more than 20,000 Gazans, including more than 8,000 children and 6,200 women. No desire for revenge can justify that.

International rules governing the ethical conduct of war prohibit the direct targeting of civilians, but permit striking military targets even when it is known that the strikes will kill some civilians. The rules derive from what is known as the doctrine of double effect, a line of ethical thought that goes back to 13th-century Catholic theologian Thomas Aquinas. According to this view, an act that would otherwise be wrong, such as killing an innocent person, may be permissible if it is an unintended side effect of a permissible act, such as striking a military target when waging a just war, provided that the benefit gained outweighs the harm.

The vagueness of this last provision -- known as the proportionality requirement -- makes it possible for Israel to claim that it is acting within the rules of war. But more detailed investigations of specific military actions that Israel has undertaken make it clear that its attacks are going beyond any reasonable belief that the military benefits outweigh the harms to civilians.

The New York Times investigated one such military operation, an airstrike carried out on Oct. 31 on a residential neighborhood in Jabalia, in northern Gaza. The target, Israel said, was Ibrahim Biari, a senior Hamas commander who it said was “central” to the Oct. 7 massacre. Israel claimed that Biari was killed. A British conflict monitor said that 126 civilians were also killed, and other estimates were higher still. The Times quoted Larry Lewis, a former US State Department senior adviser on civilian harm, as saying: “The willingness to accept this level of harm to civilians is far beyond what I have seen in operations in the past.”

If Biari was central to the scenes I witnessed in the video, he was capable of extraordinary evil and ought to be brought to justice. But that does not justify killing 126 civilians.

Alongside Israel’s willingness to kill many civilians in order to achieve nonessential military goals, we must put its restriction of food, water and fuel in Gaza. Human Rights Watch has accused Israel of using starvation as a weapon of war, which is a war crime. That makes plausible the startling claim made last month by Jordan’s foreign minister, Ayman Safadi, that Israel is engaged in “a systematic effort to empty Gaza of its people,” which he said would fall “within the legal definition of genocide.”

That is a shocking allegation, especially for a nation-state founded in the aftermath of genocide. Israel’s government could refute it by pausing hostilities and allowing into Gaza the essential supplies that its people need.

Peter Singer

Peter Singer is a professor of bioethics at Princeton University. -- Ed.

(Project Syndicate)