There is a manmade famine in Yemen, even if it has not been officially acknowledged. The man who made it is Mohammed bin Salman, the crown prince of Saudi Arabia, and there is strong prima facie evidence that he should be charged with causing starvation in an international court.

Along with the comparably culpable Mohamed bin Zayed, crown prince of the United Arab Emirates, Bin Salman launched a war against Houthi rebels in Yemen in 2015, and pursued it primarily through actions intended to reduce people to desperation in areas under Houthi control, compelling them to submit.

Mass starvation may not have been Bin Salman’s initial intent, but it soon became evident that this would be the outcome. He nonetheless persisted in waging war using methods that had the predictable effect of depriving millions of people of food, clean water, medicine and other basic necessities.

Among these methods is an economic blockade, enforced by air, sea and land, that restricts the import of essential items and limits the possibility of Yemenis travelling abroad for medical care. According to UN experts, the blockade “is essentially using the threat of starvation as a bargaining tool and an instrument of war”.

There has also been a systematic targeting of agricultural and fishing infrastructure – as well as medical facilities, water infrastructure and economic infrastructure (including civilian businesses that provide essential employment) – by aerial bombardment, as documented in part by the Yemen Data Project. The central bank has been transferred from the capital, Sana’a (controlled by the Houthis), to Aden (controlled by the recognised government), while salary payments to government employees have been stopped and intermittent restrictions placed on humanitarian aid. Military offensives in and near Hodeidah – the main port for the northern part of Yemen, through which most of Yemen’s food, fuel and aid flow – have had an especially debilitating impact.

Taken together, over more than three years, these actions amount to the use of starvation as a method of warfare, which is prohibited by the Geneva conventions, the Rome statute of the international criminal court, and UN security council resolution 2417 on armed conflict and hunger, which was unanimously adopted in May.

In his defence, Bin Salman could claim that the suffering of the Yemenis doesn’t meet the necessary threshold of severity, because the UN hasn’t declared famine in Yemen (although the UN’s assessments show that millions of Yemenis have been suffering severe food insecurity for several years, and this is enough to kill in large numbers).

His defence counsel might also argue that enough food has been arriving in Yemen, through commercial imports and smuggling, and that the markets in Sana’a and other cities remain well stocked. They may also claim there are many other causes of hunger, such as Yemen’s pre-existing poverty and food insecurity, and that starvation is an unintended byproduct of legitimate military and political-economic decisions.

On top of that will no doubt be arguments that the blockade and air attacks were designed to compel the Houthis to withdraw from the areas they occupied and negotiate peace, and involved a lower human cost than the alternative of a massive ground assault. Closing the central bank and not paying salaries were acts of economic policy, justifiable in the context of economic crisis and the Houthi control of the capital. And Saudi Arabia has been funding humanitarian efforts.

But with the collapse in salaried employment, millions of Yemenis are starving because they can’t afford to buy food. That qualifies as famine. The Saudi leader would have known that Yemen was already vulnerable to food crisis. This makes his actions even more culpable. As for Saudi’s humanitarian response, it’s a small downpayment for the billions of dollars in reparations for which the perpetrators of the famine would be liable if found guilty.

At the outset of the war, it might have been reasonable to hope that pressure would force the Houthis to submit. Since it takes months to starve people, a brief period of hardship would not have involved a level of suffering disproportionate to the military objective. But, within months of the launch of the war, humanitarian agencies were warning of crisis, and there were no indications of Houthi surrender. By persisting with this method of war, Bin Salman knew for sure that thousands of Yemeni children would die from hunger and disease.

The Houthis also used starvation as a weapon. But the fact that the other side is also responsible does not make Bin Salman innocent. That he has consistently received support from London, Paris and Washington also makes him no less blameworthy – it only raises the question of who else might be complicit.

To date, no international court has prosecuted a case of starvation crimes. Bin Salman would be an appropriate first accused.

