Israel’s “sustained policy of obstructing the movement of humanitarian assistance into the territory” pushed Human Rights Watch co-founder Aryeh Neier to view the assault on Gaza as a genocide.

A widely respected humanitarian law expert who has resisted using the term “genocide” for Israel’s killing of tens of thousands of Palestinians in Gaza—a word used “sparingly” in the international human rights movement, he noted—said Tuesday that he has concluded a genocide is indeed taking place, evidenced particularly by Israel’s blocking of humanitarian aid.

Aryeh Neier, who co-founded Human Rights Watch in 1978, served as its executive director for 12 years, and also led the American Civil Liberties Union and the Open Society Foundations, noted in an essay in The New York Review of Books that his organizations have used the term “genocide” to describe few mass killings.

Neier was not convinced of South Africa’s genocide claim against Israel when it argued its case with the International Court of Justice in January, even though he was “deeply distressed” by the human impact of Israel’s relentless U.S.-backed bombing campaign in Gaza.

The 2,000-pound bombs being used against Gaza’s population of 2.3 million Palestinians were “clearly inappropriate,” wrote Neier in the magazine’s June 6 issue. “Yet I was not convinced that this constituted genocide.”

Neier wrote that he believed at the time that Israel’s retaliation against Hamas for the October 7 attack it led in southern Israel could “include an attempt to incapacitate” the Palestinian group, necessitating the wide-scale assault on Gaza, where it operates.

“I am now persuaded that Israel is engaged in genocide against Palestinians in Gaza,” wrote Neier, whose family escaped Nazi Germany as refugees when he was an infant. “What has changed my mind is its sustained policy of obstructing the movement of humanitarian assistance into the territory.”

Israel’s intent to block aid—and to treat Gazans as “collectively complicit for Hamas’s crimes”—has been clear since shortly after the October 7 attack, when Defense Minister Yoav Gallant said: “There will be no electricity, no food, no fuel, everything is closed. We are fighting human animals and we act accordingly.”

“I am now persuaded that Israel is engaged in genocide against Palestinians in Gaza. What has changed my mind is its sustained policy of obstructing the movement of humanitarian assistance into the territory.”

The result of that policy, wrote Neier, has been the deaths of at least 28 Palestinian children from starvation, according to numbers released by the Gaza Health Ministry in April.

“That number could multiply many times over if reports on food insecurity are valid,” he wrote, citing warnings from U.S. Agency for International Development Administrator Samantha Power and World Food Program Executive Director Cindy McCain that famine has already taken hold in parts of Gaza.

Under the “complete siege” ordered by Gallant and Prime Minister Benjamin Netanyahu, noted Neier, Israel has severely restricted the number of aid vehicles allowed into Gaza, where the population relied on deliveries from about 500 aid trucks per day before the current escalation. Trucks have been subjected to “time-consuming and onerous inspections,” with shipments turned away for including items like children’s medical scissors and maternity kits.

Neier also cited Israel’s killing of more than 200 aid workers and its persuading of international donors to stop funding the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA)—based on unproven allegations that a dozen of its 13,000 Gaza-based staffers had connections to Hamas—as evidence that Israel is taking numerous steps to stop aid from getting to Gaza’s starving population, while killing at least 35,173 Palestinians.

Jameel Jaffer, executive director of the Knight First Amendment Institute at Columbia University, said in response to Neier’s essay that “no one has more authority among human rights advocates than” the author.